be happy--an illusion

This is in the cement in the sidewalk of my neighborhood..Now, if the light source here is from the left th letters are RAISED..If the light source is from the right, the Letters are carved into the sidewalk (sunken) stare at the image and watch your brain switch from the two realities..quite fun are these optical illusions..that is why I am here, to make your day interesting. Like a court jester without the curly shoes.