minimal mosaic

image 1 image 2 image 3 image 3 image 3 image 3 image 3 image 3 image 4
image 1
× image 2
image 2
× image 1 image 3
image 3
× image 2 image 3
image 3
× image 3 image 3
image 3
× image 3 image 3
image 3
× image 3 image 3
image 3
× image 3 image 3
image 3
× image 3 image 4
image 4
× image 3