http://imgur.com/a/4cR1s#0
8 blocks. You have 2 inputs for setting to 0 (bottom) and 1 (top), 1 input for (write->not->read; in the floor) and a 4th input for "mem cell active"
These inputs lead to 4 ANDs (2 right: write, 2 left: read, 2 top: set/get 1, 2 bot: set/get 0), 2 ORs and 2 NOTs in...