The square symbols of the series above have two origins, that's why the first half of them is "trasparent" and the other half is not. But I want (and set, I promise!) all of them to be open (i.e. "white" filled), like the triangles or the circles, with the same parameters! Any idea of why does this happen?

jose.

set %(1,@D) -an 0;
// set 1st dataplot not transparent

Animated mode is used to produce realtime drawing effect, as the following script shows how one can move the %C trace up by 0.2

set %C -an 1;
%C+=0.2;
plot %C;
plot -v; // disable windows repaint