Confusing Concrete
Keeping unwanted strangers from wandering into your yard and causing a ruckus (or knocking on your door to sell you vacuums and magazines) can be tricky. You can go the traditional route and install a fence, or you can go for a subtle and startling solution by building a big concrete block that only a monster truck on high lifts could climb.
The cool part about this deterrent is that it’s all an optical illusion. There’s no giant block. The driveway is completely flat, but the entryway’s obtuse angles and the different shading in the upper part of the driveway give the concrete a three-dimensional look that fools the eyes into thinking it’s a raised platform.