Horizontal lines run left to right, parallel to the horizon, with slope 0 and equation y = k. Vertical lines run top to bottom, perpendicular to the horizon, with undefined slope and equation x = k.

Optical illusions are powerful tools to reveal your perception power. These show how your brain and eyes work together to process the visual stimuli. These illusions exploit or trick your brain into ...

Straight lines can be drawn in any direction. Horizontal lines go left and right. Vertical lines go up and down. Parallel lines are a fixed distance apart and will never meet, no matter how long they ...