It appears the hacker made wooden frames lined with mesh (to fit the size of the openings) and cable tied the frames to the HYLLIS post. Hinges were added to the frames at the side of the HYLLIS to access the interior of the cage. This is definitely one possibility and there’s no need to drill into metal, which makes things easier.
For me, I’ll want to simplify the above hack further.
First, I get large rolls of chicken wire. (Hopefully, they are tough enough to withstand squirrels’ sharp little teeth?)
I will wrap the wire around the 2 sides and back of the HYLLIS, leaving the front for the door. Secure the chicken wire to the posts of the HYLLIS with cable ties or cut up strands of the chicken wire itself, if you want things to look more seamless.
Make sure to secure it in as many spots as necessary to keep the wire taut and firmly against the HYLLIS. We don’t want those pesky squirrels getting in through gaps and holes.
Basically, I’ll make a rectangle frame and then staple the wires to the wood frame. I’ll get a couple of hinges, a metal drill bit to make new holes in the HYLLIS post and secure this new frame to the HYLLIS post.
Much easier to make just one frame than 12!
Tada! Squirrel proof garden cage.
Let us know what you end up with. We would love to see it.