program Snake {
  property Position { column: int = 0, row: int = 0 }
  property Segment { index: int = 0 }

  const GRID_WIDTH: int = 20   const GRID_HEIGHT: int = 15   const TILE_SIZE: int = 16

  var food_column: int = 14   var food_row: int = 7   var score: int = 0

  handler DrawWorld phase Render {
    Screen.clear(Color.MidnightBlue)
    # checkerboard field — a fresh, immutable column/row each pass
    for row in 0 .. GRID_HEIGHT {
      for column in 0 .. GRID_WIDTH {
        var tile_color = Color.Charcoal
        if (column + row) % 2 == 0 { tile_color = Color.Gunmetal }
        Screen.fill_rectangle(x: column * TILE_SIZE, y: row * TILE_SIZE, width: TILE_SIZE, height: TILE_SIZE, color: tile_color)
      }
    }
    # the food, then every snake segment straight from the ECS
    Screen.fill_rectangle(x: food_column * TILE_SIZE + 3, y: food_row * TILE_SIZE + 3, width: TILE_SIZE - 6, height: TILE_SIZE - 6, color: Color.Crimson)
    for (position, segment) in query [Position, Segment] {
      var segment_color = Color.LimeGreen
      if segment.index == 0 { segment_color = Color.MintGreen }        # brighter head
      Screen.fill_rectangle(x: position.column * TILE_SIZE + 1, y: position.row * TILE_SIZE + 1, width: TILE_SIZE - 2, height: TILE_SIZE - 2, color: segment_color)
    }
    Screen.draw_text(x: 6, y: 4, text: "SCORE", color: Color.White, scale: 1)
    Screen.draw_number(x: 52, y: 4, value: score, color: Color.Gold, scale: 1)
    Screen.show()
  }
}