Answer: Pixel Puzzle #142

The hidden picture is a sailing boat!

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 = [
    "0000100000",
    "0000110000",
    "0000111000",
    "0000111100",
    "0000200000",
    "2222222222",
    "0222222220",
    "3333333333",
]
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 × white, 5 × white
• Row 2: 4 × white, 2 × white, 4 × white
• Row 3: 4 × white, 3 × white, 3 × white
• Row 4: 4 × white, 4 × white, 2 × white
• Row 5: 4 × white, 1 × brown, 5 × white
• Row 6: 10 × brown
• Row 7: 1 × white, 8 × brown, 1 × white
• Row 8: 10 × blue