Nome Sweet Homes for pets

I recently stumbled upon an article discussing ways to build your house to be more suitable for your pets. The article discussed small features in homes to enable cats to better travel through the house. These types of modifications appear rather simple and fun.

Maybe architecturally changing a home to fit a pet is a step too far?
If so, how about other modifications to the home? I know I have seen the plywood ‘cover’ on parts of the step grates to make it more gentle on Rover’s paws.

I built my bed extremely high off the ground so my 80 pound┬áhusky would have a cozy ‘cubby’ for sleeping.

Have you tried any modifications that have failed? Succeeded? Would you consider architectural modifications to your home in order to make it more suitable for your pet?