A online interactive color wheel with CIELab or HSV color space
Here's a working implementation of a color wheel for OSWeb (>= 1.3.5). It shows a color circle in either CIELab or HSV color space, and the participant can select up to four colors. This can be useful for visual-working-memory experiments.
Update June 18, 2020: Color circle now randomly rotates (6 possible rotations).