What command to use...taper? Please help!

Good evening,
I’ve been trying to make these corridor panels fit along these two black lines, so the panels get smaller but maintain the same detailing. On something like photoshop I know you can Transform then Distort but I can’t seem to find a way of solving this on Rhino. It seems like such an easy task!?

Dear Jessie
check out
_cageEdit

http://docs.mcneel.com/rhino/5/help/en-us/commands/cageedit.htm

if your final Data has to be machined, the resulting surface-quality might not fit - if it is just for design-issues _cageedit is fine.
hope that helps - best - Tom