Across and down together

Challenge 5 of 16

Now both arguments get a number of their own. The shape moves right and downward on every frame, and because the two steps are equal it travels at a neat diagonal.

Set both speeds to 5.

Your code JavaScript

Set both speeds to 5.

Console print() output

0 / 50 frames · 400×400

Target

Yours

Results

Press Run to check your code

Penalties: none this run

Report this challenge

Lesson Down and Across

Which way is forward.

x counts across from the left, y counts downward from the top. That second one catches everybody: adding to y sinks a shape, and taking away from it makes it climb. A negative speed is not "backwards" — it is whichever direction that axis counts from.

Two numbers, no conversation.

x = x + speedX; and y = y + speedY; are two separate instructions, and neither knows the other exists. Equal steps happen to draw a 45 degree line; make the across step three times the down step and you get a long shallow drift instead. The angle is just the ratio of the two numbers — challenges 6 and 7 are the same code with the numbers swapped, and they look nothing alike.

Reading two at once.

The readout along the bottom now shows both numbers, on the target as well as on yours. Challenge 13 gives you nothing else: drag to a frame, read what each number has reached, and work backwards to the steps.