Test your eye for color
This activity belongs to the GeoGebra book Lights Out (Games with solutions).
Now we propose the following game: try to reproduce exactly a certain color, the one with the upper rectangle. To do this, you have the R, G, B (red, green, blue) sliders that allow you to vary the color of the lower rectangle.
Only when the two rectangles have exactly the same RGB color will the message that you have achieved it appear.
If you find it too difficult, you can choose to display a hint that will guide you to the desired color.
Author of the construction of GeoGebra: Rafael Losada