Different Take on Toddler-Proof Doorknob

In my ongoing attempts to stay ahead of Lincoln's ability to do himself harm, I have secured the door to my shop with a new, higher doorknob.

Now simply shutting the door renders it toddler-proof.

Lincoln was super-excited about me drilling holes in the door, right up until I removed the old doorknob and he understood what was actually going on. Then there were tears.