func (p *Piece) collides(field *Field, x, y int, angle Angle) bool {
	size := len(p.blocks)
	for i := 0; i < size; i++ {
		for j := 0; j < size; j++ {
			if field.IsBlocked(x+i, y+j) && p.isBlocked(i, j, angle) {
				return true
			}
		}
	}
	return false
}
func (p *Piece) collides(field *Field, x, y int, angle Angle) bool {
	size := len(p.blocks)
	for i := 0; i < size; i++ {
		for j := 0; j < size; j++ {
			if field.IsBlocked(x+i, y+j) && p.isBlocked(i, j, angle) {
				return true
			}
		}
	}
	return false
}
// collides returns a boolean value indicating whether
// the piece at (x, y) with the given angle would collide with the field's blocks.