diff -Nuar b/Makefile a/Makefile
--- b/Makefile	1999-12-27 22:27:24.000000000 +0000
+++ a/Makefile	2009-09-21 11:49:40.000000000 +0000
@@ -46,26 +46,14 @@
 
 .SUFFIXES: .dvi .tex .w
 
-.tex.dvi:
-	tex $*.tex
+all: libgb.a test_io test_graph test_flip demos
 
-.w.c:
-	if test -r $*.ch; then ctangle $*.w $*.ch; else ctangle $*.w; fi
-
-.w.tex:
-	if test -r $*.ch; then cweave $*.w $*.ch; else cweave $*.w; fi
-
-.w.o:
-	make $*.c
-	make $*.o
-
-.w:
-	make $*.c
-	make $*
-
-.w.dvi:
-	make $*.tex
-	make $*.dvi
+%.dvi: %.tex
+	tex $^
+%.c: %.w
+	ctangle $^
+%.tex: %.w
+	cweave $^
 
 DATAFILES = anna.dat david.dat econ.dat games.dat homer.dat huck.dat \
         jean.dat lisa.dat miles.dat roget.dat words.dat
@@ -175,3 +163,9 @@
 
 fulltar: $(ALL) ERRATA ANSI AMIGA PROTOTYPES MSVC
 	tar cvf sgb.tar $(ALL) ERRATA ANSI AMIGA PROTOTYPES MSVC
+
+$(DEMOS) lib tests test_io test_graph test_flip: libgb.a
+
+demos: $(DEMOS)
+
+.PRECIOUS: .o .c .tex