63 — ASCII art — drawing with characters

Guide 47 drew one growing row of #. Here the rows keep their shape, so a picture appears: shapes built from * and spaces. Two tools do the work — string multiplication repeats a character, and a loop repeats a row. Nested loops turn those rows into triangles and a diamond.

#Steps

1. "*" * 5 is one string with five stars, and " " * 2 + "*" * 3 glues two spaces to three stars. Strings can multiply and add like numbers:

   show "*" * 5
   show " " * 2 + "*" * 3
   

   copyrun it →

   It prints ***** and then *** (two spaces, three stars).

2. A for loop turns the repeated string into a triangle. Each pass prints one row, and the row grows with i:

   for i in range(1, 6):
       show "*" * i
   

   copyrun it →

   It prints a right triangle from one star to five.

3. range(5, 0, -1) counts down, so the rows shrink. The same loop body draws an upside-down triangle:

   for i in range(5, 0, -1):
       show "*" * i
   

   copyrun it →

   It prints five stars down to one.

4. A centered row needs spaces on the left. For row i of a five-row shape, n - i spaces push the stars to the middle, and 2 * i - 1 stars is an odd count — 1, 3, 5, and so on:

   n = 5
   for i in range(1, n + 1):
       spaces = " " * (n - i)
       stars = "*" * (2 * i - 1)
       show spaces + stars
   

   copyrun it →

   It prints the pointed top half of a diamond.

5. Now the whole picture in one program. The diamond reuses the centered row twice — once counting up for the top, once counting down for the bottom. Save ascii.nme:

   # ascii.nme — drawing shapes with characters.
   # Run: nme r ascii
   #
   # Shapes are built from two ideas: string multiplication
   # repeats a character, and nested loops repeat a row.
   # A right triangle, an upside-down triangle, and a diamond.
   
   n = 5
   
   show "Right triangle:"
   for i in range(1, n + 1):
       show "*" * i
   
   show ""
   show "Upside-down triangle:"
   for i in range(n, 0, -1):
       show "*" * i
   
   show ""
   show "Diamond:"
   for i in range(1, n + 1):
       spaces = " " * (n - i)
       stars = "*" * (2 * i - 1)
       show spaces + stars
   for i in range(n - 1, 0, -1):
       spaces = " " * (n - i)
       stars = "*" * (2 * i - 1)
       show spaces + stars
   

   copyrun it →

6. Run it:

   nme r ascii
   

   copy

   Right triangle:
   *
   **
   ***
   ****
   *****
   
   Upside-down triangle:
   *****
   ****
   ***
   **
   *
   
   Diamond:
       *
      ***
     *****
    *******
   *********
    *******
     *****
      ***
       *
   

   copy

   The diamond starts with one star, widens to nine, and narrows back to one. The bottom loop starts at n - 1 so the widest row is not printed twice.

7. Korean writes the same steps with 말해, 공백, and 별. The full Korean program is in the Korean guide.

#Try it yourself

Change n from 5 to 8 and rerun — every shape grows. Then build a letter H: two vertical bars of stars with a middle row of n stars, all in one loop that chooses the middle row with an if. Replacing "*" with "@" gives the same shapes in a different character.

#What you learned

• "*" * 5 repeats a string; " " * 2 + "*" * 3 builds a centered row.
• A loop repeats a row; the loop variable sets each row's length.
• range(n, 0, -1) counts down and shrinks the rows.
• A diamond is one centered row counted up and then down again.
• Nested loops — a loop that decides each row's shape — draw pictures.