I am a huge fan of observation hives, but prefer that they are fully functional rather than being an interrupt to a normal hive. So I've been researching designs, and then modified plans to make a very simple 8 frame hive. It is 2 frames deep, with the bottom pair being deeps, for easy installation of the brood, and 3 pairs of mediums above. Both sides open, a debris drawer cleans out what falls through the bottom screen without taking the hive outdoors, and bees enter and exit through a 1" clear plastic tube. My signature has a link to the plans, which do not require a router, table saw or other special woodworking equipment. I have added a 1 1/4" hole center top, currently plugged, but which will open into a 2-frame honey super that can be added & removed without taking the whole hive outdoors. I will update the plans with details on that project as it is completed.