[P] Representing states in a neural network input layer • r/MachineLearning

As a little project, I'm working on building out a neural network that learns to play a snake game. The game is composed of a max 20x20 board where each cell is either an apple, a snake, or a wall. One way I thought of encoding that data in the input layer would be to have a 20x20 400 neuron input layer where each neuron has one of 3 different states signaled by neuron value. Say, 0 apple, 0.5 snake, 1 wall. Is encoding multiple states in a single neuron like this a good idea?