Chapter Two -- Repeat

Lesson 1:

Introducing REPEAT

• Reconsider

  • drawing a square: Repeat a group of commands -- FD 50 RT 90

  • drawing stairs: Repeat a group of commands -- FD 20 RT 90 FD 20 LT 90

  • drawing a dotted line: Repeat a group of commands -- PD FD 10 PU FD 10

• REPEAT

  • Whenever a group of commands is repeated more than once

  • Format: REPEAT <number> [<a group of commands>]

  • Example:

    1. REPEAT 4 [FD 50 RT 90] -- draw a square

    2. REPEAT 5 [FD 20 RT 90 FD 20 LT 90] -- draw five stairs

    3. REPEAT 10 [PD FD 10 PU FD 10] -- draw a dotted line with 10 segments

Activities: A)  D)  E)  F)

 

Exploration: Paper work, program, and compare

 

Lesson 2:

Using REPEAT to Make a Rectangle

• A rectangle can be divided into two right angles: upper-left, and lower-right
• Each right angle can be drawn with a set of two commands:
  • FD 30 RT 90 FD 60 RT 90
• The right angle is repeated twice:
  • REPEAT 2 [FD 30 RT 90 FD 60 RT 90]

Activities: A), B), C)

Exploration: Paper work, program, and compare

 

Lesson 3:

Positing Your Design on the Screen

• Move the turtle without drawing: PENUP -- PU
• Draw a picture at a specific position
• Predicting:
  • DRAW
  • PU FD 100 PD
  • REPEAT 4 [FD 30 RT 90]
• Draw a cross
  • DRAW
  • LT 45
  • REPEAT 4 [FD 50 BK 50 RT 90]

Activities:    A)  B)  C)  D)

Exploration: Paper work, program, and compare

 

Lesson 4:

Patterns Using REPEAT

• Figure out patterns that constitute a given picture
• Figure out how patterns are drawn
• Use repeat as possible as you can
• Examples:
  1. Draw two separate squares
     • REPEAT 4 [FD 30 RT 90]
     • PU RT 90 FD 70 LT 90 PD
     • REPEAT 4 [FD 30 RT 90]
  2. Draw two separate squares with different orientation (tilt shape)
     • Change the turtle's heading before it draws the squares
  3. Predict:
     • REPEAT 5 [FD 20 LT 30 BK 40 RT 30]

Activities:    A)  B)  C)  D)  E)

Exploration: Paper work, program, and compare

 

Lesson 5:

Putting it all Together

• Use REPEAT to make a square
• Draw a picture at any position
• Identify patterns
• Use REPEAT to make patterns and designs
• Repeat patterns

Activities: A) B) C) D) E) F)