Answer: Pixel Puzzle #313

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",
    "033333333300",
    "033333333300",
    "034333334300",
    "033333333300",
    "033555553300",
    "033333333300",
    "006666666000",
    "006666666000",
    "006666666000",
    "000500500000",
]
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*
 *********
 **+++++**
 *********
  =======
  =======
  =======
   +  +

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, 9 × teal, 2 × white
• Row 4: 1 × white, 9 × teal, 2 × white
• Row 5: 1 × white, 1 × teal, 1 × yellow, 5 × teal, 1 × yellow, 1 × teal, 2 × white
• Row 6: 1 × white, 9 × teal, 2 × white
• Row 7: 1 × white, 2 × teal, 5 × navy, 2 × teal, 2 × white
• Row 8: 1 × white, 9 × teal, 2 × white
• Row 9: 2 × white, 7 × orange, 3 × white
• Row 10: 2 × white, 7 × orange, 3 × white
• Row 11: 2 × white, 7 × orange, 3 × white
• Row 12: 3 × white, 1 × navy, 2 × white, 1 × navy, 5 × white