int pic=0; // picture number for saving movies void picture() {String S="data/P/f"+Format0(pic++,3)+".tif"; saveFrame(S); } int fn=0; // number of the file last read String Format0(int v, int n) {String s=str(v); String spaces = "00000000000000000000000000"; int L = max(0,n-s.length()); String front = spaces.substring(0, L); return(front+s); };