docs: function isIrrelevant(tile) {
  	return !tile
  		|| !tile.physics
  		|| !tile.physics.matterBody
  		|| !tile.physics.matterBody.body
  		|| !tile.physics.matterBody.body.vertices
  		|| !tile.physics.slopes
  		|| !tile.physics.slopes.neighbours
  		|| !tile.physics.slopes.edges;
  }