19 Y := 3  variable
20 SIMPLE += $(Y)
21 Y := 4  variable
25 Y := 3  variable
26 RECURSIVE += $(Y)
27 Y := 4  variable
32 Y := 3  variable
33 UNDEFINED_VARIABLE += $(Y)
34 Y := 4  variable
39 Y := B  variable
40 $(X)$(Y) := 5