I started off by making a mock-up on Powerpoint.

I then colour-coded the images I used and cropped them.

I then made this joiner in Photoshop.

After finishing putting this joiner together in Photoshop, I changed the brightness and contrast of each of the images. I also added another image fragment to the bottom left.

I made a few more small tweaks and this is my final result:

I also made a version using Gaussian Blur: