A 20-year-old college student has rebuilt Portal, Valve’s 2007 space-bending game, from the ground up, on—wait for it—a graphing calculator. In a display that puts the old calculator versions of Mario ...
A horizontal line means the object is moving at a constant speed. The gradient of the line = the rate of change of speed. The steeper the line, the greater the increase in speed. The area under the ...