An Exercise in Op Art

You will need five different colors and a straightedge.

On the circle below, draw the following sets of chords, each in a different color:

AI, BJ, CK, ..., RH.

AH, BI, CJ, ..., RG.

AG, BH, CI, ..., RF.

AF, BG, CH, ..., RE.

AE, BF, CG, ..., RD.

What do you notice about the finished picture?