Background:

In most neighborhoods constructed within the last century, streets are designed almost entirely for cars. The ability of a human to travel on two feet is sadly only a neglected afterthought.

As a result, many sidewalks are cracked, partially lifted up by tree roots, or otherwise irregular in a way where tripping on them is easy.

Proposal:

Obviously a person can avoid falling on an irregular surface by being diligent and walking where they’re going, but it’s hard to maintain vigilance at all times.

Thus, the following proposal: two slightly-offset laser grid projectors that are mounted on a hat (Figure 1).

The laser grid projectors serve two purposes:

• First, the projected laser grid makes it easy to see where a surface is irregular in some way: if the projected grid of squares is distorted in some way, then obviously the underlying terrain is also irregular.
• Second, the use of two projectors means that if the sidewalk is perfectly level, then the lasers will combine to make a single color. But if there is any irregularity, then one or the other laser might be occluded, leading to a different (i.e. non-mixed) color being visible.

Conclusion:

This would also be an incredible fashion accessory for any hat, as is obvious from the illustration in Figure 1.

PROS: Improves public safety.

CONS: May increase the rate of brush fires and/or melted eyeballs if people illegally increase the wattage of their laser projectors.

Originally published 2025-08-25.