Subscribe to download Hello World! [Logic, Gates and Computability]

When I opened the editor my first thought was to build something crazy with the gels. I prompty became bored with the idea. However innovation never rests! My second instinct was to see if Portal 2 could be used to build basic logic gates and to consider the game in terms of computability.

When you enter, to the left is and AND gate followed by an OR gate (I cheated somewhat and used AND and NOT to create OR rather than synthesis a unique approach). To you right is a NOT gate followed by a clock.

I've been able to make similar gates using mechanical components, but I prefer the "solid state" nature of the lasers.

The nice part about constucting these is that (1) inputs and outputs can be connected in a many-to-many relationship and (2) outputs can be set to on or off initially (with a signal toggling them). So AND is simply two input piped into one output; it won't fire if they are not both on. NOT is piping an input into an output with the output on initially. OR I synthesised from the fact that a OR b <-> NOT(NOT(a) AND NOT(b)).

I choose to use block buttons for inputs and lasters for outputs, but the choice is arbitrary. Any of the inputs and outputs should work.