Against-The-Wall Shelf Tilter Feet

These shelf feet raise the front of a free-standing shelf, so it leans safely against a wall. 

Carpeted rooms often have a board under the carpet along each wall, which tilts shelves forward in an unstable way. As people walk by, their weight on floor can cause the shelf to tilt toward them. While you could mount an anchor to a stud in the wall and attach the shelf, that solution complex and may not be allowed in apartments or other rented spaces. 

I've included a shorter, but otherwise matching model in case you need to print the back feet as well. Both should fit most square pipe-style shelves. You may have to adjust the scale.

Printing Notes:
• Any sturdy plastic (such as PETG).
• No supports needed.
• Brim not needed. 
• Infill ≥ 50%.
• Remember to use a ruler or calipers to check the internal measurements of your shelf legs. 

Assembly: 
• Remove the stock feet from the front of the shelf. 
• Insert the new, taller ones.
• The fit should be snug, but able to be pushed in without damage. If the foot is slightly loose, it can be glued in place to avoid it falling out when moving the shelf.
• If the shelf is propped against a painted or wallpapered wall, I recommend sticking foam-backed tape on the shelf's points of contact. Double-sided tape with backing left in place will also work. This is to avoid the shelf rubbing on the wall as people walk by and damaging the paint or wallpaper.

Today I Learned:
IKEA began selling flat-pack furniture in 1956 after one of their technicians had to saw the legs off a table to fit it in his car. https://en.wikipedia.org/wiki/Ready-to-assemble_furniture#History