I went to the theater last night and saw a rather mediocre adaptation of a French farce. You know it's not a great play when you start wondering if the fabric used for one character's dress would make an interesting kilt.

This particular fabric was one of those that in a certain light appears one color but in another light or from a different angle appears to be another color. In this case the colors were red and blue and consequently varying shades of violet. As she moved the fabric moved so the colors all shifted. It reminded me of some discussion that we've had here regarding pleating to the stripe where the color is hidden behind the fold of the pleat only to be revealed as the wearer moves.

In the few minutes I've spent googling, I haven't hit upon the correct search terms to discover what this fabric is. Anyone know?