Half Circle Fish Tank I Need Help A Fish Tank Divider Question.?

I need help a fish tank divider question.? - half circle fish tank

I have a 55g tank, but I'm willing to put a section in the middle of the forehead, in a semi-circle design with ..... I can a domino effect, which have held some reptiles, a little water and land perfer the sun ..... this is impossible, but I am looking for ideas that would work and safe for my fish and reptiles.

Please e ideas.