Skip to main content
PrimaSTEM is built on the idea of LOGO. Seymour Papert and his colleagues created this language for children in 1967. In LOGO a child types commands and a turtle draws on the screen. In PrimaSTEM the child places tokens on the board, and a wooden robot with a marker draws on paper. No keyboard, no screen, no text. This page is for teachers who know LOGO or Scratch, and for anyone who wants to see what the tokens really do.

​
Concepts on the board

Each command has its own saved value: changing Forward does not change Left. When the board is switched off, all values go back to the defaults: 150 mm, 90°, 1 s for Pause. To change the default step for good, use the “Set Default Step Length” service token (see Device & Setup). The child does the calculating. The robot carries out the program exactly. Each example has a link. It opens the simulator with this program on the board and runs it.

​
Square

Board: top row Function × 4. Bottom row: Forward 300, Right.
Run in the simulator

Program on the board

What the robot draws

For ages 4–6, leave out the numbers: Forward and Right with no numbers draw a square with 15 cm sides.

​
Equilateral triangle

Board: top row Function × 3. Bottom row: Forward 400, Right 120.
Run in the simulator

Program on the board

What the robot draws

Why 120 and not 60? The robot turns by the outer angle. The three turns together must make a full turn: 3 × 120 = 360.

​
Five-pointed star

Board: top row Function × 5. Bottom row: Forward 400, Right 144.
Run in the simulator

Program on the board

What the robot draws

5 × 144 = 720: the robot turns around twice, and the line closes into a star.

​
Circle

Board: top row Function × 36. Bottom row: Forward 25, Right 10.
Run in the simulator

Program on the board

What the robot draws

A circle is a polygon with many short sides: 36 × 10° = 360°.

​
Square spiral (variable and arithmetic)

Board: top row Forward 30, Function × 20. Bottom row: Right, Forward +30.
Run in the simulator

Program on the board

What the robot draws

Forward 30 sets the saved value. Each time the function runs, “+30” makes the side 30 mm longer: 60, 90, 120 and so on. The first Forward 30 resets the value, so if you press ▶ Start again, you get the same spiral.

​
Hexagon (an angle from division)

Board: top row Right 360, Right ÷6, Function × 6. Bottom row: Forward 200, Right.
Run in the simulator

Program on the board

What the robot draws

Right 360 makes one full turn and saves 360. Right ÷6 divides the saved value and turns 60°. In the function, Right with no number takes 60° again. The two turns at the start only change where the robot faces before it draws; the shape stays a hexagon. The board divides in whole numbers and drops the remainder. For the shape to close, divide 360 by a number that leaves no remainder: 3, 4, 5, 6, 8, 9, 10, 12. For example, 360 ÷ 7 gives 51°, and the heptagon misses closing by 3°. More drawings: Drawing Examples. PrimaSTEM covers the core of LOGO turtle graphics. A few things work differently, by design:
  • One pair, one command and one value. A pair of cells holds a command and at most one value: a number, a repeat or an operation. This keeps a program readable even for a four-year-old.
  • No conditions (if). The program runs the same way every time. Only the dice and Random Movement add chance.
  • The Function has no named parameters. You call it with a repeat, and it uses the values set before the call (see the table above).
  • Program length: 6 pairs in the main row, 5 in the Function.
  • You put the marker in by hand when the child wants the robot to draw.
When a child outgrows the board, the same robot works with Scratch.

​
Further reading

Last modified on October 26, 2026