Below are 3 personal posters designed by the design Firm Calango. They were created as part of a personal project not to serve any purpose other than to be visually interesting.
The depth of the shapes has been captured really well by using fading colours along the contours of the shapes making them appear 3D. The intruding white line that repeats throughout the three posters almost forces your eyes to read the imagery from the top right down to the bottom left. This works well as a forceful device over the audience almost narrowing their viewpoint to what lies around the direction of the line.
Simple shapes and psychedelic colours really appeal to me, even if these posters aren't necessarily solving a problem they they definitely have a very valuable purpose. That purpose literally being to be visually attractive and compelling.