[jitter] Dammaged Gridshapes

Hi,
When I rotate the gridshape with the following Patch, the object seems to dissolve in certain moments and you see inside of it. What causes this effect, and how can i avoid it?

Thanx 4 help

attached is a screenshot of the effect
here's the patch:
#P window setfont Tahoma 10.;
#P flonum 296 44 35 10 0 0 0 6583 0 0 0 221 221 221 222 222 222 0 0 0;
#P flonum 251 43 35 10 0 0 0 6583 0 0 0 221 221 221 222 222 222 0 0 0;
#P flonum 213 43 35 10 0 0 0 6583 0 0 0 221 221 221 222 222 222 0 0 0;
#P flonum 174 43 35 10 0 0 0 6583 0 0 0 221 221 221 222 222 222 0 0 0;
#P window linecount 1;
#P newex 158 69 130 431423498 pak erase_color 1. 1. 0.5 1.;
#P connect 4 0 0 4;
#P connect 3 0 0 3;
#P connect 2 0 0 2;
#P connect 1 0 0 1;
#P window clipboard copycount 5;

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