https://www.openlearning.com/u..../bucknerkristofferse
https://output.jsbin.com/jetemufiyi/
A cat flap allows you to give your pet more freedom while saving you the burden of letting them in and out. It can also help your pet feel less stressed and prevent them from escaping the house when they're not wanted. To install a cat flap, measure the distance from the bottom of the cat's stomach down to the floor. Draw a line across the door's frame. Check that the line is level with a spirit level. 1. The type of door If you're installing an