The big ideaA shape is move and turn, repeated, and a square turns ninety degrees four times.
How it works
A pen block draws a line as the sprite moves. Pen down means draw, and pen up means move with no line.
A shape is move and turn, repeated. A repeat block draws all the sides with just a few blocks.
A square corner is 90 degrees, and a full spin is 360 degrees. Four turns of 90 degrees make one full spin.
The turns of a closed shape add up to 360 degrees. When the turns make a full spin, the line closes.
A turn that is too small leaves a gap.
Example 1: A square
The stack says repeat 4 times: move 100 steps, then turn 90 degrees.
Four turns of 90 degrees: 4 × 90 = 360.
That is a full spin, so the last line meets the first and the square closes.
Example 2: A gap
Noor's first stack turns 80 degrees at each corner.
Four turns of 80 degrees: 4 × 80 = 320.
320 is less than a full spin of 360, so there is a gap.
The mix-up to fix: change 80 to 90.
Example 3: A triangle
Repeat 3 times: move 100 steps, then turn 120 degrees.
Three turns of 120 degrees: 3 × 120 = 360.
A full spin, so the shape closes with three sides.
Example 4: A hexagon
Repeat 6 times: move 100 steps, then turn 60 degrees.
Six turns of 60 degrees: 6 × 60 = 360.
A full spin, so the shape closes with six sides.
Words to know
sprite
A character you move with blocks. Noor's was a little pencil.
pen down
A block that makes the sprite draw a line as it moves.
degrees
A way to measure a turn. A square corner is 90 degrees.
repeat block
Does the blocks inside it again and again.
Watch out
A turn that is too small, such as 80 degrees, leaves a gap, and the corners look too pointy.
Pen up draws no line. Put pen down before the sprite moves if you want a line.
The number of times to repeat is the number of sides: 3 for a triangle, 4 for a square, 6 for a hexagon.
A closed shape's turns always add up to 360 degrees.
Try it
Does pen up draw a line as the pencil moves?
How many degrees is a full spin?
A square turns 90 degrees at each of 4 corners. How many degrees is that in all?
Which closes a square: turning 80 degrees four times, or turning 90 degrees four times?
A triangle uses 3 turns of 120 degrees. What do they add up to?
Answers: 1. No · 2. 360 · 3. 360 · 4. Turning 90 degrees four times · 5. 360
Try at homeWalk a square on the floor: take four steps, turn a quarter turn, and repeat four times. Then try turning a smaller turn and see where you end up. Count the turns: four quarter turns make one full spin.
For grown-upsDo the Mission: mark a square on the floor with chalk or string and walk it together: four steps, a quarter turn, and repeat four times. Then try a smaller turn and see where you end up.
Open these notes on screenScan the code, or go to tutorpip.com.