Four Square is the 95th level in Chip's Challenge 1. As noted, eight chips exist in Four Square, which make the problem of which chips to collect quite baffling.
Begin by sliding D, then take the red key, push the block on the left into the teleport and follow it, then slide back out, open the red lock on the top edge and take the chip on the right side (be careful of walkers; fortunately this is a short route). Replace this with the other red key on the top edge of the "four square", then slide the top block through to exchange this for a yellow key, which will be used on the right side to reach the second chip and exit.
