To create the pattern using the Mosaic Filter in GIMP
Create a transparent layer and set your background color to the desired color (I picked a yellow).
Go to Filters > Distorts > Mosaic and set the highlighted ones below (you can experiment with the others, but make sure you set the highlighted ones):
Duplicate the mosaic pattern, and run the mosaic filter one more time, but this go-around, set the Tile Spacing to a little bit higher (I used 3.0). Click OK.
Run Gaussian Blur on this new layer and adjust the blend mode, if desired. Merge both layers together. Here's my result:
Now, try experimenting with the Perspective Tool to get the angle you want. Here's a screenshot of mine:
Then, try the suggestions provided by the other members above.
Hope this helps.
I'd rate you as an upper-middle-lower-mod with pro-novice-inter tendencies.....and a twist of lime! Of course, my rating scale is completely objectively subjective, but ALWAYS consistently inconsistent.