A light shading element includes a base plate having a light-transmitting hole, a light shading blade for at least partially blocking the light-transmitting hole, and first and second driving mechanisms pivotally connected to the light shading blade to drive its movement in a plane. The first and second driving mechanisms are pivotally connected to the light shading blade through a first pivot point and a second pivot point, respectively. The light shading blade is configured to selectively move close to and away from the light-transmitting hole to respectively block and unblock the light-transmitting hole. The first pivot point moves along an arcuate trajectory under driving of the first driving mechanism, and the second pivot point is capable of moving along another arcuate trajectory around the first pivot point under driving of the second driving mechanism, when the first pivot point is at any position along the arcuate trajectory.

A walking aid that projects visual indications corresponding to repositioning of the walking aid. At least one indication for each foot is projected simultaneously. Each indication has dimensions corresponding to a circle or oval. The spacing between each indication can be modified to achieve different step length patterns. Each indication is projected at separate positions on a surface beneath the walking aid. Each position of the separate positions remains relatively static while the walking aid is both stationary and being displaced.