Dear Stev thank you very very much. This  was the kind of answer I looked for. I am very grateful about that. Karl > Am 03.03.23 um 18:45 schrieb Steve Lelievre: >> $fn=100; >> xn=0.5; >> yn=3; >> zn=0.8; >> difference() { >>    linear_extrude(zn*0.99) circle(r=4); >>    linear_extrude(zn*1.01) union() { >>       for (i=[0:45:315]) rotate(i) translate([0,2]) resize([xn,yn]) circle(1);    // 315 = 360 - 45 >>       for (i=[22.5:45:337.5]) rotate(i) translate([0,2.88]) circle(d=0.5);  // 337.5 = 360 - 22.5 >>    } >> }