```go
package main

import (
	"bufio"
	"fmt"
	"os"
)

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	grid := make([]string, 4)
	for i := 0; i < 4; i++ {
		scanner.Scan()
		grid[i] = scanner.Text()
	}
	for i := 0; i < 3; i++ {
		for j := 0; j < 3; j++ {
			count := 0
			for di := 0; di < 2; di++ {
				for dj := 0; dj < 2; dj++ {
					if grid[i+di][j+dj] == '#' {
						count++
					}
				}
			}
			if count != 2 {
				fmt.Println("YES")
				return
			}
		}
	}
	fmt.Println("NO")
}
```