This is a test of your device's pixel density.

If your Aspect and Desity match then your screen is 1x

If your Aspect is 1/2 (50%) of your Desity then your screen is 2x

If your Aspect is 1/3 (33%) of your Desity then your screen is 3x

If your Aspect is 1/4 (25%) of your Desity then your screen is 4x