Grade 3 · Laser & Vinyl · Lesson 36

Puzzle Postcard

Create a message that becomes a small, solvable jigsaw puzzle.

Time2 × 60 minutes + adult laser cuttingTeamsTeams of 2–4EquipmentxTool laser cutters

Project inspiration · 3 images

See, build, and test

Use these images to understand the kind of making, details, and testing involved. They are inspiration—not designs students must copy.

Finished student example for Puzzle Postcard
01Finished project
The same postcard's large mixed puzzle pieces and engraved clue
02Construction detail
Students timing a solve of the same postcard puzzle
03Student testing

Student directions · Grade 3

What will you make and do?

You will make a small picture puzzle that communicates a message when its pieces are assembled. The pieces should be sturdy and fit in their intended places.

Teacher overview: Students will plan the specific object described below, make and test a first version, then use their results to improve it. Read one step together, demonstrate the unfamiliar action, and let students complete that step before moving on.

  1. 1Plan your project

    Draw a bold original postcard image with a clear message. Sketch two ways to divide it into a few large, differently shaped pieces.

  2. 2Make the first parts

    Make a paper or cardboard puzzle first. Mix the pieces and ask a partner to solve it without seeing your plan.

  3. 3Put it together

    Revise the dividing lines into teacher-approved closed vector paths. An adult checks piece size and operates the laser cutter; keep pieces appropriate for the class.

  4. 4Test it fairly

    Give viewers the same starting arrangement and instructions. Time their solves and note confusing edges or pieces that fit incorrectly.

  5. 5Improve one part

    Change one confusing boundary or picture clue. Repeat a comparable solve test and describe the difference.

  6. 6Show and turn in

    Present the assembled and mixed puzzle, image plan and solve-time notes. Explain how the message remains clear.

How will you know it works?

  • Finished picture communicates a clear message
  • All pieces fit in only the intended places
  • Challenge is fun but solvable

Before you move on

Tell a partner what you are making. Point to the part you will work on next. Draw or dictate your test notes if writing slows you down.

Machine cutting, printer setup and electrical power-on require adult approval. A basic-materials model is a valid way to demonstrate the design when equipment is unavailable.

Keep your plan, test notes and before-and-after evidence with the printable design brief below. Use the detailed teacher plan and any coding guide for tool instructions. These steps continue across the lesson’s meetings, not all in one sitting.

For teachers

Engineering standards

This shows how the lesson connects to the national NGSS engineering standards and what student work you can collect.

Assessed

3-5-ETS1-1

Teams define the user or purpose and identify measurable success criteria plus size, material, and time limits.

What students show: Problem statement with criteria, constraints, and a labeled planning sketch.
Practiced

3-5-ETS1-2

Students draw and compare at least two possible shapes, layouts, or joining methods before choosing a design.

What students show: Two ideas and a criteria-based explanation of the selected features.
Assessed

3-5-ETS1-3

Teams prototype in paper or cardboard, give three new users the mixed pieces and time each solve without offering hints, revise one feature, and repeat the test.

What students show: Before-and-after prototype, test notes, and an evidence-based revision statement.

Materials

  • Blank postcard templates
  • Bold markers and collage paper
  • Envelopes or reusable storage sleeves
  • Paper, index cards, or thin cardboard for first prototypes
  • Pencils, dark markers, rulers, tape, and child-safe scissors
  • Computer or tablet with beginner vector-drawing software
  • Teacher-approved laser material such as cardboard, plywood, or acrylic
  • Calipers or a teacher-provided material-thickness gauge

Teacher preparation

  1. Choose and verify one material approved for the exact xTool model; record its measured thickness.
  2. Prepare a simple demonstration of cut lines, engrave areas, closed paths, and minimum feature size.
  3. Set up a paper-first prototype station and a material-saving size limit.
  4. Create the file rule G3_36_Team##_v1.
  5. Plan an adult-only file check and cutting queue; students observe from the designated safe area.

Step by step

How to teach it

Day 1 · 0–15

Meet the need

  1. Introduce the mission: Design a postcard puzzle another student can solve in one to three minutes and understand when complete.
  2. Name the user or purpose, then agree on criteria and constraints.
  3. Examine how tabs, slots, outlines, and engraved marks appear in sample pieces.
Day 1 · 15–35

Imagine and compare

  1. Each student sketches a different solution using simple shapes.
  2. Teams compare the ideas against the criteria.
  3. Select or combine features and label all cuts, slots, folds, and engraved details.
Day 1 · 35–60

Prototype first

  1. Build a full-size paper or cardboard version.
  2. Use the same test procedure: give three new users the mixed pieces and time each solve without offering hints.
  3. Find one weak, confusing, loose, or oversized feature and revise it.
Day 2 · 0–35

Make the vector file

  1. Trace or rebuild the improved design with bold closed paths.
  2. Measure every slot from the actual material thickness and keep tiny details out.
  3. Use the teacher checklist for size, line type, loose pieces, naming, and material use.
Day 2 · 35–60

Cut, assemble, and retest

  1. A trained adult performs the final safety and material check and operates the laser.
  2. Students assemble the finished parts without forcing joints.
  3. Repeat the original test, compare results, and explain one next improvement.

Assessment

  • Problem statement includes a purpose, criteria, and constraints.
  • Two ideas are compared before the final design is chosen.
  • Paper or cardboard prototype is tested before final cutting.
  • Vector file uses closed paths, readable details, and efficient material placement.
  • Revision responds to recorded test evidence.

Supports & extensions

  • Provide editable circle, rectangle, tab, slot, and name-tag starter files.
  • Offer printed picture directions and a color-coded cut-versus-engrave key.
  • Let students draw on paper for an adult or partner to trace digitally.
  • Use larger parts, fewer joints, and pre-measured slot options when helpful.
  • Extension: nest parts to reduce waste or compare two slot widths using measured fit data.

Safety & responsible use

  • Students do not operate the laser cutter.
  • A trained adult verifies material identity, settings, focus, ventilation, fire monitoring, and file placement.
  • Never laser-cut PVC, vinyl, unknown plastics, unidentified coated materials, or any material not explicitly approved.
  • Keep the lid closed during operation and follow the xTool model's required supervision and emergency procedures.
  • Check cut edges and splinters before student assembly; use only teacher-approved adhesives and hand tools.

No-machine alternative

Make the final project from cardstock, corrugated cardboard, recycled folders, or foam board using child-safe scissors and teacher-prepared pieces. Keep the same criteria, comparison, test, and revision cycle.

Printable student design brief

The challenge

Design a postcard puzzle another student can solve in one to three minutes and understand when complete.

Success criteria

  • Finished picture communicates a clear message
  • All pieces fit in only the intended places
  • Challenge is fun but solvable

Constraints

  • Uses 6–12 pieces
  • No piece is smaller than the teacher's size guide
  • Includes an engraved title or clue

Engineer’s notes

Our user or purpose is…
Our two ideas are different because…
The test showed…
We changed… because…
Our cut lines are…
Our engraved details are…
Next time we would…
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