MUTATIS MUTANDIS
A colorful object appears above the grid for each turn.
The object is circular, triangular, square, or star-shaped. The object is one of three colors.
Direct the object to a column using the arrow keys.
Attempting to direct an object to an occupied column will cause the shape and color to progress through a cycle.
If the operation intended would result in a red circle, green triangle, blue square, or non-green star, the operation is not performed, and the given object is stacked in the column it is directed to.
When all three objects in a row are of the same color or shape, the row is cleared.
Experiment to determine the specific cycling mechanism!