diff --git a/README.md b/README.md
index 90d65a4..033992c 100644
--- a/README.md
+++ b/README.md
@@ -14,6 +14,9 @@ cc src/modal.c -o bin/modal
 
 ```
 bin/modal examples/hello.modal
+	-v Print version
+	-q Quiet mode, no step printing
+	-n Infinite mode, no rewrites limit
 ```
 
 ## Credits
diff --git a/examples/io_repl.modal b/examples/io_repl.modal
deleted file mode 100644
index 5e96b63..0000000
--- a/examples/io_repl.modal
+++ /dev/null
@@ -1,11 +0,0 @@
-?(?-) (This example demonstrates how to keep the runtime active between prompts.)
-
-<> ((You said: quit\n) send) ((You quit.) print ')
-<> (?: print ') (?:)
-<> (?: send) (?: wait stdin)
-<> (wait ?~) ((You said: ?~\n) send)
-<> (' ?x) (?x ')
-
-(Say something, or type "quit": \n) print '
-
-wait stdin
\ No newline at end of file
diff --git a/examples/postcard.modal b/examples/postcard.modal
new file mode 100644
index 0000000..478b784
--- /dev/null
+++ b/examples/postcard.modal
@@ -0,0 +1,9 @@
+
+<> (what is ?x) (is ?x a (programming language))
+<> (is ?x a ?y) (or, is ?x (a virtual machine))
+<> (or, is ?x ?y) (?x is ?y <> ?y (a meta-language))
+<> ((a meta-language)) modal
+<> (?x is ?x) (?(?: ?:) ?x)
+
+what is modal
+
diff --git a/examples/repl.modal b/examples/repl.modal
new file mode 100644
index 0000000..15cbd7f
--- /dev/null
+++ b/examples/repl.modal
@@ -0,0 +1,8 @@
+?(?-) (This is a fully functional Modal REPL.)
+
+<> quit EOF
+<> wait?~ (?~ wait!)
+<> (?: print) ?:
+<> (EOF wait!) (Bye.\n print)
+
+(Say something, or type "quit":\n) print wait!
\ No newline at end of file
diff --git a/examples/sierpinski.modal b/examples/sierpinski.modal
new file mode 100644
index 0000000..9c2a50a
--- /dev/null
+++ b/examples/sierpinski.modal
@@ -0,0 +1,21 @@
+?(?-) (Rules)
+
+<> (* (. > (. ?x))) (* (. (. > ?x))) 
+<> (. (. > (* ?x))) (* (. (* > ?x))) 
+
+?(?-) (Physics)
+
+<> (Tri > (?x ?y)) (Tri (?x > ?y))
+<> (Tri (?x > (?y ?z))) (Tri (?x (?y > ?z)))
+<> (?x (?y > (?z ?n))) (. (?y (?z > ?n)))
+<> ((?x > ())) (< ())
+<> (Tri < (* ?^)) (?(?: ?:) (*?^ \n))
+<> ((?x < ?y)) (< (?x ?y))
+
+?(?-) (Print)
+
+<> (Tri.join ?x ?:) (Tri > ?x ?:)
+<> (Tri.dup ?x ?^) (Tri.join ?x ?^)
+<> (Tri < ?x) (Tri.dup (. ?x) (?x \n))
+
+?(?* (Tri < (?*))) ...............*...............
\ No newline at end of file
diff --git a/examples/tests.modal b/examples/tests.modal
index f8e329e..cc8a36b 100644
--- a/examples/tests.modal
+++ b/examples/tests.modal
@@ -1,74 +1,82 @@
 ?(?-) (This example tests various aspects of the implementation.)
 
-?(?-) (Inline rules)
+?(?-) (Early Test Primitives)
 
-<> ((?x -> ?y)) (<> ?x ?y)
-(nap -> (tap =))
+<> (?x = ?x ?n test) (?(?: ?:) (#pass ?n\n))
 
-nap tap test
+<> (ghost) ()
+
+?(?-) (Formatter)
+
+?((?x ?y) one) aaa(bbb) = one (formatter 1) test
+?((?x ?y) one) (bbb)aaa = one (formatter 2) test
+(a b c ) = (a b c) (formatter 3) test
+( a b c) = (a b c) (formatter 4) test
+(  a  b  c  ) = (a b c) (formatter 5) test
+(a b c  ( a b c )  ) = (a b c (a b c)) (formatter 6) test
 
 ?(?-) (Empty replacements)
 
-<> (?x pop-plain)
-<> (?x pop) ()
-<> (ghost) ()
+(ab cd () ghost) = (ab cd ()) (empty 1) test
+(ab cd ghost ()) = (ab cd ()) (empty 2) test
+(ab ghost cd ()) = (ab cd ()) (empty 3) test
+(ghost ab cd ()) = (ab cd ()) (empty 4) test
+(ghost) = () (empty 5) test
 
-abc def pop-plain = abc test
-abc def pop = abc test
-(ghost) = () test
+(q ?((?x ?y ?z) (?x ?y)) a b c) = (q a b) (empty 6) test
+(q ?((?x ?y ?z) (?x ?z)) a b c) = (q a c) (empty 7) test
+(q ?((?x ?y ?z) (?y ?z)) a b c) = (q b c) (empty 8) test
 
-?(?-) (Basic replacements)
+<> (prefix/pop ?x) ()
+<> (?x suffix/pop) ()
 
-<> (replace-name (foo)) ((bar) =)
-
-replace-name (foo) (bar) test
+(ab prefix/pop cd ef) = (ab ef) (empty 9) test
+(ab cd suffix/pop ef) = (ab ef) (empty 10) test
 
 ?(?-) (Basic register setups)
 
-<> (dup (?x)) ((?x ?x) =)
-<> (swap (?x ?y)) ((?y ?x) =)
-<> (compare (?x ?x ?x)) ((#t) =)
+<> (dup (?x)) (?x ?x)
+<> (swap (?x ?y)) (?y ?x)
+<> (compare (?x ?x ?x)) (#t)
+<> (rotate (?x (?y (?z)))) (?y (?z (?x)))
+<> (unused ?x) ?y
 
-dup (abc) (abc abc) test
-swap (abc def) (def abc) test
-compare (abc abc abc) (#t) test
+(dup (abc)) = (abc abc) (basic 1) test
+(swap (abc def)) = (def abc) (basic 2) test
+(compare (abc abc abc)) = (#t) (basic 3) test
+(rotate (abc (def (ghi)))) = (def (ghi (abc))) (basic 4) test
+(unused hey) = (?y) (basic 5) test
 
-?(?-) (Empty register replacement)
+?(?-) (Substring registers)
 
-<> (replace-empty ?x) (?y)
+<> (connect ?x ?y ?z) (?x-?y?z)
+<> (prefix-?x) (?x-suffix)
 
-replace-empty abc = ?y test
-
-?(?-) (Guards setups)
-
-<> (join (String ?x) (String ?y)) ((?x ?y) =)
-
-join (String abc) (String def) (abc def) test
+connect foo bar baz = foo-barbaz (substring 1) test
+prefix-anything = anything-suffix (substring 2) test
+?(foo QQQ) foobar = foobar (substring 3) test
 
 ?(?-) (Lambdas)
 
-?((?x) ((?x ?x) =)) abc (abc abc) test
-abc ?(?x) def = abc test
+(?(?x (?x ?x)) abc) = (abc abc) (lambda 1) test
+abc ?(?x) def = abc (lambda 2) test
 
-?(?-) (Explode)
+?(?-) (op: explode)
 
-<> (explode ?*) ((?*) =)
+(?(?* ?*) cow) = (c (o (w ()))) (explode word) test
+(?(?* ?*) (12 34 45)) = (12 (34 (45 ()))) (explode tuple) test
+(?(?* ?*) ()) = () (explode empty) test
 
-explode cow (c (o (w ()))) test
-explode (12 34 45) (12 (34 (45 ()))) test
+?(?-) (op: join)
 
-?(?-) (Implode)
+?(?^ ?^) (b (a (t ()))) = bat (join 1) test
+?(?^ ?^) (12 (34 (56 ()))) = 123456 (join 2) test
+(?(?^ ?^) ()) = () (join empty) test
 
-<> (implode ?^) (?^ =)
+?(?-) (op: unwrap)
 
-implode (b (a (t ()))) bat test
-implode (12 (34 (56 ()))) 123456 test
-
-?(?-) (Test Primitives)
-
-<> (?: print) (?:)
-<> (?x = ?x test) (#ok)
-<> (?x = ?y test) (#fail)
+?(?. ?.) (abcd) = abcd (unwrap 1) test
+(?(?. ?.) ()) = () (unwrap empty) test
 
 ?(?-) (List reversal)
 
@@ -76,5 +84,15 @@ implode (12 (34 (56 ()))) 123456 test
 <> (reverse (?*)) (reverse List (?*) ())
 <> (reverse List (?x ?y) ?z) (reverse List ?y (?x ?z))
 
-reverse (modal) = ladom test
+reverse (modal) = ladom (reverse 1) test
 
+?(?-) (Inline rules)
+
+<> ((?x -> ?y)) (<> ?x ?y)
+(nap -> (tap =))
+
+nap tap (inline 1) test
+
+?(?-) (Late Test Primitives)
+
+<> (?x = ?y ?n test) (?(?: ?:) (#fail ?n found: ?x expect: ?y\n))
\ No newline at end of file
diff --git a/makefile b/makefile
index ab918b7..24e2457 100644
--- a/makefile
+++ b/makefile
@@ -8,12 +8,14 @@ all: dest
 dest:
 	@ mkdir -p bin
 run: all bin/modal
-	@ bin/modal examples/hello.modal 2> /dev/null
-debug: bin/modal-debug
+	@ bin/modal -q examples/hello.modal
+debug: all bin/modal-debug
 	@ bin/modal-debug examples/hello.modal
-test: bin/modal-debug bin/modal
+test: all bin/modal-debug bin/modal
 	@ bin/modal -v
-	@ bin/modal-debug examples/tests.modal
+	@ bin/modal-debug -q examples/fizzbuzz.modal
+	@ bin/modal-debug -q examples/sierpinski.modal
+	@ bin/modal-debug -q examples/tests.modal
 install: bin/modal
 	cp bin/modal ~/bin/
 uninstall:
diff --git a/src/modal.c b/src/modal.c
index 5f3206b..0c1a83f 100644
--- a/src/modal.c
+++ b/src/modal.c
@@ -1,16 +1,15 @@
 #include <stdio.h>
 
 typedef struct {
-	int id;
-	char *a, *b;
+	unsigned int id, refs, ptr;
+	char *a, *b, reg[0x10];
 } Rule;
 
-static int flip, rmin = 0xff, rmax = 0x00, cycles = 0x10000;
-static Rule rules[0x1000], lambda, *rules_ = rules;
-static char dict[0x8000], *dict_ = dict;
+static int flip, quiet, cycles = 0x10000;
+static Rule rules[0x1000], *rules_ = rules, lambda;
+static char dict[0x8000], *dict_ = dict, empty;
 static char bank_a[0x4000], *src_ = bank_a;
 static char bank_b[0x4000], *dst_ = bank_b;
-static char *regs[0x100];
 
 #define spacer(c) (c <= ' ' || c == '(' || c == ')')
 
@@ -30,62 +29,17 @@ walk(char *s)
 	return s;
 }
 
-static int
-set_reg(int r, char *b)
-{
-	if(regs[r]) {
-		char *a = regs[r], *aa = walk(a), *bb = walk(b);
-		while(a < aa && b < bb)
-			if(*a++ != *b++) return 0;
-	} else {
-		regs[r] = b;
-		if(r < rmin) rmin = r;
-		if(r > rmax) rmax = r;
-	}
-	return 1;
-}
-
 static void
-put_reg(char r)
+write_reg(char r, char *reg)
 {
-	char c, *s = regs[(int)r], *ss;
-	if(!s) {
-		*dst_++ = '?', *dst_++ = r;
-		return;
-	}
-	ss = walk(s);
-	if(r == '*') {
-		int i, depth = 0;
-		if(*s == '(') { /* special explode tuple */
-			s++;
-			while(s < ss) {
-				while((c = *s) && !spacer(c))
-					*dst_++ = c, s++;
-				*dst_++ = ' ';
-				*dst_++ = '(', s++, depth++;
-			}
-		} else { /* special explode token */
-			while((c = *s++) && !spacer(c))
-				*dst_++ = c, *dst_++ = ' ', *dst_++ = '(', depth++;
-		}
-		for(i = 0; i < depth; i++)
-			*dst_++ = ')';
-	} else if(r == '.') { /* special unpack */
-		if(*s == '(') s++, --ss;
-		while(s < ss) *dst_++ = *s++;
-	} else if(r == '^') { /* special join */
-		if(*s == '(') s++, --ss;
-		while(s < ss && (c = *s++))
-			if(!spacer(c)) *dst_++ = c;
-	} else if(r == '~') { /* special stdin */
-		while(fread(&c, 1, 1, stdin) && c >= ' ')
-			*dst_++ = c;
-	} else if(r == ':') { /* special stdout */
-		if(*s == '(') s++, --ss;
-		while(s < ss) {
-			c = *s++;
+	char c, *cap = walk(reg);
+	switch(r) {
+	case ':': /* op: output */
+		if(*reg == '(') reg++, --cap;
+		while(reg < cap) {
+			c = *reg++;
 			if(c == '\\') {
-				switch(*s++) {
+				switch(*reg++) {
 				case 't': putc(0x09, stdout); break;
 				case 'n': putc(0x0a, stdout); break;
 				case 's': putc(0x20, stdout); break;
@@ -93,117 +47,178 @@ put_reg(char r)
 			} else
 				putc(c, stdout);
 		}
-	} else
-		while(s < ss) *dst_++ = *s++;
-}
-
-static char *
-match_rule(Rule *r, char *p)
-{
-	int i;
-	char c, last = 0, *a = r->a, *b = p;
-	if(rmax) {
-		for(i = rmin; i <= rmax; i++)
-			regs[i] = 0;
-		rmin = 0xff, rmax = 0x00;
+		return;
+	case '~': { /* op: input */
+		while(fread(&c, 1, 1, stdin) && c >= ' ')
+			*dst_++ = c;
+		if(feof(stdin))
+			*dst_++ = 'E', *dst_++ = 'O', *dst_++ = 'F';
+		return;
 	}
-	while((c = *a)) {
-		if(spacer(last) && c == '?') {
-			if(!set_reg(*(++a), b)) return NULL;
-			a++, b = walk(b);
-			continue;
-		}
-		if(c != *b) return NULL;
-		a++, b++, last = c;
+	case '^': /* op: join */
+		if(*reg == '(') reg++, --cap;
+		while(reg < cap && (c = *reg++))
+			if(!spacer(c)) *dst_++ = c;
+		return;
+	case '.': /* op: unwrap */
+		if(*reg == '(') reg++, --cap;
+		while(reg < cap) *dst_++ = *reg++;
+		return;
+	case '*': { /* op: explode */
+		int i, depth = 0;
+		if(*reg == '(' && reg[1] != ')') { /* tuple */
+			reg++;
+			while(reg < cap) {
+				while((c = *reg) && !spacer(c))
+					*dst_++ = c, reg++;
+				*dst_++ = ' ';
+				*dst_++ = '(', reg++, depth++;
+			}
+		} else /* token */
+			while((c = *reg++) && !spacer(c))
+				*dst_++ = c, *dst_++ = ' ', *dst_++ = '(', depth++;
+		for(i = 0; i < depth; i++) *dst_++ = ')';
+		return;
+	}
+	default:
+		while(reg < cap) *dst_++ = *reg++;
+		return;
 	}
-	c = *b;
-	return spacer(c) ? b : NULL;
 }
 
 static int
-commit_rule(Rule *r, char *s, int create)
+write_rule(Rule *r, char *s, int create)
 {
 	while((*dst_++ = *s++))
 		;
-	*dst_++ = 0;
+	*dst_ = 0;
 	if((flip = !flip))
 		src_ = bank_b, dst_ = bank_a;
 	else
 		src_ = bank_a, dst_ = bank_b;
-	if(create)
-		fprintf(stderr, "<> (%s) (%s)\n", r->a, r->b);
-	else
-		fprintf(stderr, "%02d %s\n", r->id, src_);
+	if(!quiet) {
+		if(create)
+			fprintf(stderr, "<> (%s) (%s)\n", r->a, r->b);
+		else
+			fprintf(stderr, "%02d %s\n", r->id, src_), ++r->refs;
+	}
 	return 1;
 }
 
 static int
-write_rule(Rule *r, char last, char *res)
+apply_rule(Rule *r, char *s)
 {
-	char c, *b = r->b, *origin = dst_;
-	while((c = *b++))
-		if(spacer(last) && c == '?')
-			put_reg(*b++);
-		else
-			*dst_++ = c, last = c;
-	if(dst_ == origin) {
-		while(*res == ' ') res++;
-		if(*res == ')' && *(dst_ - 1) == ' ') dst_--;
+	unsigned int i, id;
+	char c, *a = r->a, *b = r->b, *origin = dst_, *reg, *regs[0x08];
+	/* phase: clean registers */
+	for(i = 0; i < r->ptr; i++)
+		regs[i] = NULL;
+	/* phase: match rule */
+	while((c = *a++)) {
+		if(c == '?') {
+			char *pcap = walk(s);
+			id = *a++ - '0';
+			if((reg = regs[id])) { /* reg cmp */
+				char *rcap = walk(reg), *pp = s;
+				while(reg < rcap || pp < pcap)
+					if(*reg++ != *pp++) return 0;
+			} else /* reg set */
+				regs[id] = s;
+			s = pcap;
+		} else if(c != *s++)
+			return 0;
 	}
-	return commit_rule(r, res, 0);
-}
-
-static char *
-parse_frag(char *s)
-{
-	char c, *ss;
-	while((c = *s) && c <= ' ') s++;
-	if(*s != ')' && !(*s == '<' && s[1] == '>')) {
-		ss = walk(s);
-		if(*s == '(') {
-			s++;
-			while(s < ss - 1) *dict_++ = *s++;
-			s++;
+	c = *s;
+	if(!spacer(c)) return 0;
+	/* phase: write rule */
+	while((c = *b++)) {
+		if(c == '?') {
+			id = *b - '0';
+			if(id < 9 && (reg = regs[id]))
+				b++, write_reg(r->reg[id], reg);
+			else
+				*dst_++ = c;
 		} else
-			while(s < ss) *dict_++ = *s++;
+			*dst_++ = c;
 	}
-	*dict_++ = 0;
-	return s;
+	if(dst_ == origin) {
+		while(*s == ' ') s++;
+		if(*s == ')' && *(dst_ - 1) == ' ') dst_--;
+	}
+	return write_rule(r, s, 0);
+}
+
+static int
+find_register(Rule *r, char reg)
+{
+	int i;
+	for(i = 0; i < (int)r->ptr; i++)
+		if(r->reg[i] == reg) return i;
+	return -1;
 }
 
 static char *
-create_rule(Rule *r, int id, char *s)
+compile_rule(Rule *r, int id, char *src)
 {
-	r->id = id, s += 2;
-	r->a = dict_, s = parse_frag(s);
-	r->b = dict_, s = parse_frag(s);
-	return s;
+	char c, *cap;
+	int wrapped, reg;
+	r->id = id, r->ptr = 0, r->a = &empty, r->b = &empty;
+	/* phase: compile left */
+	while((c = *src) && c == ' ') src++;
+	if(c == ')' || (c == '<' && src[1] == '>')) return src;
+	r->a = dict_, cap = walk(src), wrapped = c == '(';
+	if(wrapped) src++, cap--;
+	while(src < cap) {
+		c = *src, *dict_++ = *src++;
+		if(c == '?') {
+			c = *src++, reg = find_register(r, c);
+			if(reg == -1 && c != '(')
+				r->reg[r->ptr] = c, reg = r->ptr++;
+			*dict_++ = '0' + reg;
+		}
+	}
+	src += wrapped, *dict_++ = 0;
+	/* phase: compile right */
+	while((c = *src) && c == ' ') src++;
+	if(c == ')' || (c == '<' && src[1] == '>')) return src;
+	r->b = dict_, cap = walk(src), wrapped = c == '(';
+	if(wrapped) src++, cap--;
+	while(src < cap) {
+		c = *src, *dict_++ = *src++;
+		if(c == '?') {
+			c = *src++, reg = find_register(r, c);
+			*dict_++ = reg != -1 ? '0' + reg : c;
+		}
+	}
+	src += wrapped, *dict_++ = 0;
+	return src;
 }
 
 static int
 rewrite(void)
 {
-	char c, last = 0, *cap, *s = src_, *res;
-	while((c = *s) && c <= ' ') s++;
+	char c, last = 0, *cap, *s = src_;
+	while(*s == ' ') s++;
 	while((c = *s)) {
-		if(spacer(last)) {
-			Rule *r;
-			if(*s == '<' && s[1] == '>') {
+		if(c == '(' || spacer(last)) {
+			Rule *r = NULL;
+			/* phase: rule */
+			if(c == '<' && s[1] == '>') {
 				r = rules_++;
-				s = create_rule(r, rules_ - rules - 1, s);
-				while((c = *s) && c <= ' ') s++;
-				return commit_rule(r, s, 1);
+				s = compile_rule(r, rules_ - rules - 1, s + 2);
+				while(*s == ' ') s++;
+				return write_rule(r, s, 1);
 			}
-			if(*s == '?' && s[1] == '(') {
-				r = &lambda, cap = walk(s + 1);
-				create_rule(&lambda, -1, s), s = cap;
-				while((c = *s) && c <= ' ') s++;
-				if((res = match_rule(&lambda, s)) != NULL)
-					return write_rule(&lambda, last, res);
+			/* phase: lambda */
+			if(c == '?' && s[1] == '(') {
+				cap = walk(s + 1), compile_rule(&lambda, -1, s + 2), s = cap;
+				while(*s == ' ') s++;
+				if(!apply_rule(&lambda, s)) write_rule(&lambda, s, 0);
+				return 1;
 			}
+			/* phase: match */
 			for(r = rules; r < rules_; r++)
-				if((res = match_rule(r, s)) != NULL)
-					return write_rule(r, last, res);
+				if(apply_rule(r, s)) return 1;
 		}
 		*dst_++ = last = c;
 		s++;
@@ -216,31 +231,38 @@ int
 main(int argc, char **argv)
 {
 	FILE *f;
-	int i;
-	char c, *w = bank_a;
+	int i, pl = 0, pr = 0;
+	char c, last = 0, *w = bank_a;
 	if(argc < 2)
 		return !printf("usage: modal [-vqn] source.modal\n");
 	for(i = 1; i < argc && *argv[i] == '-'; i++) {
 		switch(argv[i][1]) {
-		case 'v': /* version */ return !printf("Modal Interpreter, 18 Apr 2024.\n");
-		case 'q': /* quiet */ fclose(stderr); break;
+		case 'v': /* version */ return !printf("Modal Interpreter, 26 Apr 2024.\n");
+		case 'q': /* quiet */ quiet = 1; break;
 		case 'n': /* infinite */ cycles = 0xffffffff; break;
 		}
 	}
 	if(!(f = fopen(argv[i], "r")))
-		return !fprintf(stdout, "Invalid Modal file: %s.\n", argv[i]);
+		return !fprintf(stdout, "Modal file invalid: %s.\n", argv[i]);
 	while(fread(&c, 1, 1, f)) {
 		c = c <= 0x20 ? 0x20 : c;
-		if(w > bank_a) {
-			if(c == ' ' && *(w - 1) == '(') continue;
-			if(c == ')' && *(w - 1) == ' ') w--;
-			if(c == ' ' && *(w - 1) == ' ') w--;
-		}
-		*w++ = c;
+		if(c == ' ' && last == '(') continue;
+		if(c == ')' && last == ' ') w--;
+		if(c == ' ' && last == ' ') w--;
+		if(c == '(') pl++;
+		if(c == ')') pr++;
+		if(c == '(' && last != '?' && !spacer(last)) *w++ = ' ';
+		if(last == ')' && !spacer(c)) *w++ = ' ';
+		*w++ = last = c;
 	}
 	while(*(--w) <= ' ') *w = 0;
 	fclose(f);
+	if(pr != pl)
+		return !fprintf(stdout, "Modal program imbalanced.\n");
 	while(rewrite())
 		if(!cycles--) return !fprintf(stdout, "Modal rewrites exceeded.\n");
+	while(rules_-- > rules && !quiet)
+		if(!rules_->refs) printf("-- Unused rule: %d <> (%s) (%s)\n", rules_->refs, rules_->a, rules_->b);
+	if(!quiet) printf(".. %s\n", src_);
 	return 0;
 }
\ No newline at end of file