This version was used to verify accuracy. According to my observation, presentation times should be specified in terms of frames not milliseconds, and the use of Firefox should be avoided for experiments with brief presentation times of less than 50 ms/3 frames.
Changes
Add new properties "pixi_angle" and "pixi_rotation" to the text object
New demo program
pixi_mental_rotation.html This uses PixiJS library to rotate the stimulus charactor.