I just love them.
Here's one I think can easily be the mother of all optical illusions -- The Spinning Dancer Illusion.
Which direction do you think the silhouette dancer is spinning? Clockwise, or counter-clockwise? Try blinking several times while looking at the picture. (Hit ESC to stop the spin. Refresh the page to start the revolution again.)
很爱看一些有关错视的图片和文章。上面的插图是我个人最近满喜欢的一个。你认为图中的“舞娘”是在顺时针打转还是逆时针？当你确认了你的答案后，尝试望着图片，同时眨几下眼睛。（按下 ESC 键可让舞娘停止打转。重刷本页舞娘便重新转动。）
除此之外，上个月我自费到新加坡自由行，也去了一趟新加坡的科学馆，拍了很多很多有趣的错视图片和实验。等我整理好后再逐一 PO 上来和大家分享分享。
By the way I've been to the Singapore Science Centre on my last visit to the country. What I got back is an abundance of interesting optical illusion snapshots. I'll post them up here once I got the time to archive the photographs.
So... clockwise, or counter-clockwise?