Academics · Elementary · Grades 1–4

Write the steps.
Watch the rover follow them.

Sixteen puzzles teach the first four ideas of coding: steps in order, loops, finding a bug and planning a longer trip. Then draw a map of your own.

Play the first puzzleWhat you get
16puzzles in four worlds
11solved best with a loop
3rings for the fewest blocks

The rover puzzles

Tap blocks to build a program, then press Run. Step runs one block at a time. Watch an example shows a loop climbing three stairs.

Loading the puzzles. If nothing appears, turn on JavaScript.

Four ideas every programmer uses

Each world of four puzzles is built around one of them, in the order they are usually taught.

Sequence

Order matters

The rover does exactly what the blocks say, top to bottom. Forward then Turn left ends in a different square than Turn left then Forward.

Loop

Say it once

Three stairs take twelve steps. A Repeat block holding the four steps of one stair does the same job with five blocks.

Debugging

Find the one wrong step

Every coder writes bugs. The skill is running the program slowly and spotting the first step where what happens stops matching what you meant.

Decomposition

Split the trip

A long drive is a few short ones. Find the part that repeats, loop it, then add the steps that come before and after.

What you get

Academics · ElementaryFree

What you finish with
Sixteen solved puzzles with a ring score for each, practice with sequences, loops and debugging, a map of the student’s own that the page has checked, and a printed record or paper puzzle to take to class.
Who it is for
Students in grades 1 to 4 meeting coding for the first time, the parents and homeschool families working beside them, and teachers who want a station, a warm-up or a paper activity.
Format
Browser puzzle game. Works by touch, mouse or keyboard on a phone, tablet or computer. Prints a record of solved puzzles and any single puzzle as a paper worksheet; saves the record as a text file.
Access
Free. No account and no sign-in. Programs and rings are saved only in this browser; no names are asked for and nothing is sent to Caveat.
Where it lives
The Elementary space in Caveat Academics.
Support
Questions, a correction or a request: team@caveatacademic.com.

How to use it

  1. Read the goal above the map, then tap Forward, Turn left and Turn right to build the program.
  2. Press Run to watch it, or Step to run one block at a time. If the rover bumps, the block that ran is marked.
  3. Tap any block to change it, move it or delete it. In the second world, add a Repeat block and put the repeating steps inside.
  4. Solve it again with fewer blocks for three rings, then open Make your own and draw a map for someone else.

Play the first puzzle

How the puzzles work

What counts as a block, how the best score is known, and how to use the puzzles with a young child.

How a puzzle is scored

  • Every block counts as one, the Repeat block included. A Repeat holding four blocks is five blocks.
  • Three rings for a program with the fewest blocks possible, two rings for up to two blocks more, one ring for any program that gets the rover home with every crystal.
  • The fewest is proved. When this page is built, a search tries every shorter program for each map, Repeat blocks included, and finds none that works. Together the sixteen best programs use 88 blocks.
  • A run ends when the rover reaches the base with every crystal, hits a rock, would leave the map, or runs out of blocks. The block that was running stays marked.
  • Your own map is checked by trying every drive, shortest first, so the page can say for certain whether it can be solved and how many moves the shortest drive takes.

For the adult nearby

Grades 1 and 2 do best with someone reading the goal aloud and asking “what will the rover do next” before each run. Left and right are from the rover’s point of view, which is the hard part at this age; turning your body the way the rover faces helps.

Grades 3 and 4 can work alone. When a child solves a puzzle the long way, ask which steps repeat before showing the Repeat block. In Find the bug, have them use Step and say aloud what each block should do.

Away from the screen, print a puzzle, tape a grid on the floor and let one child be the rover while another reads the program. Nothing here needs an account, and no names are asked for.

The sixteen puzzles

WorldPuzzleFewest blocksShortest drive, movesWhat it asks for
Steps in orderFirst drive33Forward and turns only
Steps in orderAround the corner55Forward and turns only
Steps in orderPast the rock55Forward and turns only
Steps in orderCrystal first77Forward and turns only
Say it once, repeat itThe long road26Needs a Repeat block for three rings
Say it once, repeat itUp the stairs511Needs a Repeat block for three rings
Say it once, repeat itLap of the pond614Needs a Repeat block for three rings
Say it once, repeat itRound the bend510Needs a Repeat block for three rings
Find the bugWrong turn55One bug to fix
Find the bugOne short25One bug to fix
Find the bugOut of order511One bug to fix
Find the bugOne block too many614One bug to fix
Plan the tripOut and back611Needs a Repeat block for three rings
Plan the tripCrystal ridge813Needs a Repeat block for three rings
Plan the tripThe snake road812Needs a Repeat block for three rings
Plan the tripOver the mountain1016Needs a Repeat block for three rings

Sources

  1. Computer Science Teachers Association, K–12 Computer Science Standards (revised 2017), Algorithms and Programming: for grades K–2, following and creating step-by-step instructions, programs with sequences and simple loops, and debugging them (1A-AP-08, 1A-AP-10, 1A-AP-14); for grades 3–5, programs with sequences, loops and conditionals and testing and debugging (1B-AP-10, 1B-AP-15). The puzzles cover sequences, loops and debugging; conditionals are left for later.
  2. K–12 Computer Science Framework (2016), core concept Algorithms and Programming and the practices Recognizing and Defining Computational Problems and Testing and Refining Computational Artifacts.
  3. Seymour Papert, Mindstorms: Children, Computers, and Powerful Ideas (Basic Books, 1980): the Logo turtle that moves forward and turns, and debugging as a normal part of learning.
  4. The fewest-block figures come from an exhaustive search written for this page (guide/suite/cgp_levels.py); each one is re-run through the page’s own engine in the page’s tests.

The maps, the rover and the puzzles are original to Caveat. A puzzle game is practice with the ideas, not a full computer science course. Support: team@caveatacademic.com.