Here's a complete cheat to get you started:
Graphics3D 640,480 camera=CreateCamera() MoveEntity camera,0,0,-50 light=CreateLight(2) PositionEntity light,1000,1000,-100 rope_top=CreateSphere(6) EntityColor rope_top,255,255,0 PositionEntity rope_top,0,20,0 rope_end=CreateSphere(6) EntityColor rope_end,255,0,0 PositionEntity rope_end,0,-10,0 swing=0 rope_length=20 Repeat PointEntity rope_end,rope_top MoveEntity rope_end,0,0,EntityDistance(rope_end,rope_top)-rope_length TranslateEntity rope_end,Sin(swing),-.1,0 swing=swing+1 UpdateWorld RenderWorld Flip Until KeyHit(1)