Answer: Pixel Puzzle #146

The hidden picture is the sun!

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 = [
    "000010000",
    "010010010",
    "001111100",
    "001222100",
    "111222111",
    "001222100",
    "001111100",
    "010010010",
    "000010000",
]
symbols = " #@"

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

When you run it, it prints:

    #
 #  #  #
  #####
  #@@@#
###@@@###
  #@@@#
  #####
 #  #  #
    #

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: 4 × white, 1 × yellow, 4 × white
• Row 2: 1 × white, 1 × yellow, 2 × white, 1 × yellow, 2 × white, 1 × yellow, 1 × white
• Row 3: 2 × white, 5 × yellow, 2 × white
• Row 4: 2 × white, 1 × yellow, 3 × orange, 1 × yellow, 2 × white
• Row 5: 3 × yellow, 3 × orange, 3 × yellow
• Row 6: 2 × white, 1 × yellow, 3 × orange, 1 × yellow, 2 × white
• Row 7: 2 × white, 5 × yellow, 2 × white
• Row 8: 1 × white, 1 × yellow, 2 × white, 1 × yellow, 2 × white, 1 × yellow, 1 × white
• Row 9: 4 × white, 1 × yellow, 4 × white