so i'm making a falling tiles thing, and i need to find out what's the best setup of the different colored tiles.

this is a random setup i just made

this is the old setup - the issue with the cyan tiles is standing on most of them lets you be right next to every color(see the cyan tile in the upper left corner)
neither of these are very good, so i want to know what's the best setup?
should i add another color?
should i add multiple more colors?
should i just rearrange the colors i have?
should i use large tiles or small ones?
or a mix of the two?
should i add any special features?