Kaleidosketch is a kaleidoscope-inspired symetry drawing program. The idea is pretty simple. You draw in the canvas, and Kaleidosketch creates symetry by rotating and reflecting your drawing in real time. You have control over virtually every aspect of the process. You can change the number of rotations, whether your drawing is reflected, the center of rotation, the line width, color, and how that color changes as you draw.
Kaleidosketch relies on the HTML canvas element introduced in the still very new HTML 5 specification. This, unfortunately, means that browser support is limited. Kaleidosketch works in the latest releases of Firefox and Safari, and for the most part, in Opera.
Firefox 3.0 and Safari 4.0 support all the features of Kaleidosketch.
Opera 9.2 doesn't support picking up a color from the canvas. Opera 9.5 and 9.6 have a bug that leads to gray fringes around lines and causes problems if alpha is set below 100%. This issue is fixed in the beta version of Opera 10, but a separate issue present in all versions of Opera still leads to slightly strange-looking results with alpha less than 100%.