##Blitz 2D/3D, 126 bytes
Blitz 2D/3D, 126 bytes
Graphics 180,180
ClsColor 255,255,255
Color 128,0,128
While 1
Cls
ang#=ang+3
Plot 90+67*Cos(ang),90+67*Sin(ang)
Delay 500
Wend
Unfortunately, this language is only supported on Windows (though it may run in Wine).