Hi there,

Recently, I started to learn maple. I came across a problem. 

I entered following codes:

with(plots);

ball := proc (x, y) fieldplot([x, y], x = -1 .. 1, y = -1 .. 1) end proc;

ball(1,1);      

However, it showed me Error, (in plots/animate) bad range arguments -10. = -10 .. 10, -10. = -10 .. 10.

could someone tell me how to put fieldplot into procedure？ Very much appreciated.