Because the colours contrast.
My red and green car :d
You use the decoder in Poptropica by matching the red letter with the green letter for example if it says r=d, you get the green d and put it underneath the red r. If you don't get it just watch the walk through. P.S Read File X vertically.
Red :D
Red Dark green
it would be green :D
blue, green, red, orange and purple :D
Red and green (of course) and then silver and gold :D
red blue yellow green ofc :D
d
If you need red/cyan and green/magenta 3d glasses, you can get it from people like the 3dstoreindia or search Google with 3d anaglyph glasses.
I only know where 3 are, sorry about that. Red: Train Station Purple: Main room in Bearywood Mall Green: Inside Pawsitively Green Center Hope these help! :D
LaLa-Yellow Tinky Winky-Purple Po-Red Dipsy-Green