Answer: Pixel Puzzle #231

The hidden picture is a rocket!

The finished pixel picture: a rocket.
Here’s what the colours make.

The picture as Python

Here is the same picture stored as numbers in a Python list. The program reads each number and prints a symbol for it, so you can see the picture appear in the Python shell.

picture = [
    "0001000",
    "0011100",
    "0022200",
    "0223220",
    "0233320",
    "0223220",
    "0222220",
    "0222220",
    "1222221",
    "1104011",
    "0004000",
    "0045400",
]
symbols = " #@*o+"

for row in picture:
    line = ""
    for number in row:
        line = line + symbols[int(number)]
    print(line)

When you run it, it prints:

   #
  ###
  @@@
 @@*@@
 @***@
 @@*@@
 @@@@@
 @@@@@
#@@@@@#
## o ##
   o
  o+o

Squashing the picture smaller

Computers often save space with a trick called run-length encoding. Instead of storing every pixel, they count how many of the same colour are in a row. Here’s this picture written that way:

Show the run-length code
  • Row 1: 3 × white, 1 × red, 3 × white
  • Row 2: 2 × white, 3 × red, 2 × white
  • Row 3: 2 × white, 3 × white, 2 × white
  • Row 4: 1 × white, 2 × white, 1 × blue, 2 × white, 1 × white
  • Row 5: 1 × white, 1 × white, 3 × blue, 1 × white, 1 × white
  • Row 6: 1 × white, 2 × white, 1 × blue, 2 × white, 1 × white
  • Row 7: 1 × white, 5 × white, 1 × white
  • Row 8: 1 × white, 5 × white, 1 × white
  • Row 9: 1 × red, 5 × white, 1 × red
  • Row 10: 2 × red, 1 × white, 1 × orange, 1 × white, 2 × red
  • Row 11: 3 × white, 1 × orange, 3 × white
  • Row 12: 2 × white, 1 × orange, 1 × yellow, 1 × orange, 2 × white