Answer: Pixel Puzzle #265

The hidden picture is a robot!

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 = [
    "000001100000",
    "000002200000",
    "011111111110",
    "013111111310",
    "011111111110",
    "011444444110",
    "011111111110",
    "005555555500",
    "005555555500",
    "005555555500",
    "005555555500",
    "000400400400",
]
symbols = " #@*o+"

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

When you run it, it prints:

     ##
     @@
 ##########
 #*######*#
 ##########
 ##oooooo##
 ##########
  ++++++++
  ++++++++
  ++++++++
  ++++++++
   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: 5 × white, 2 × red, 5 × white
• Row 2: 5 × white, 2 × grey, 5 × white
• Row 3: 1 × white, 10 × red, 1 × white
• Row 4: 1 × white, 1 × red, 1 × yellow, 6 × red, 1 × yellow, 1 × red, 1 × white
• Row 5: 1 × white, 10 × red, 1 × white
• Row 6: 1 × white, 2 × red, 6 × navy, 2 × red, 1 × white
• Row 7: 1 × white, 10 × red, 1 × white
• Row 8: 2 × white, 8 × pink, 2 × white
• Row 9: 2 × white, 8 × pink, 2 × white
• Row 10: 2 × white, 8 × pink, 2 × white
• Row 11: 2 × white, 8 × pink, 2 × white
• Row 12: 3 × white, 1 × navy, 2 × white, 1 × navy, 2 × white, 1 × navy, 2 × white