Plot2d behaves very strangely. I will file a bug report unless somebody tells me I am doing something stupid. (%i1) g(s):=block([s__],s__:s,remvalue(s),s__)$ (%i2) g(2); (%o2) 2 (%i3) plot2d(g,[t,1,2]); Warning: Illegal `remvalue' attempt: s Warning: Illegal `remvalue' attempt: s etc... The plot however is fine. Michel