The simple and direct design of the original Hexagon shelf was perfect for showing off 3D prints and more. But at 150% I was unsure how well it would hold heavier items, so I designed a small support that fits perfectly underneat. Glued to the shelf it should help to hold some of the weight, and stop the shelf from sagging and put a twisting force on the screws.  

The file fits the 100% stock shelf print, so resize depending on what size you want to print the shelf.