+ if (!(scr[idx++] = grise_screen())) {
+ return -1;
+ }
+ if(!(scr[idx++] = polytest_screen())) {
+ return -1;
+ }
+ if (!(scr[idx++] = plasma_screen())) {
+ return -1;
+ }
+ if (!(scr[idx++] = bump_screen())) {
+ return -1;
+ }
+ if (!(scr[idx++] = thunder_screen())) {
+ return -1;
+ }
+ if(!(scr[idx++] = metaballs_screen())) {
+ return -1;
+ }
+ if(!(scr[idx++] = greets_screen())) {
+ return -1;
+ }
+ if(!(scr[idx++] = infcubes_screen())) {
+ return -1;
+ }
+ num_screens = idx;
+
+ assert(num_screens <= NUM_SCR);