Skip to content
Back of the Box Builds

Back of the Box Builds

LEGO Alternate Builds!

  • SETS
    • Adventurers
    • Aquazone
    • Belville
    • BATMAN™
    • BIONICLE
    • Building Set with People
    • Castle
    • Duplo
    • Fabuland
    • Harry Potter
    • Holiday and Event
    • LEGOLAND
    • Model Team
    • Pirates
    • Space
    • Star Wars
    • Technic
    • Train
    • Town
    • Universal Building Set
    • Western
    • More Sets
    • Misc
  • USEFUL LINKS
    • Submit Instructions!
    • New Instructions
    • New Official Sets
    • New Alternate Builds
    • Minifigs
    • Very Small Builds
    • Small Builds
    • Medium Builds
    • Large Builds
    • Extra Large Builds
    • How BOTBB was Built
  • THIS IS AN INDEPENDENT SITE NOT AUTHORIZED OR SPONSORED BY THE LEGO GROUP
Bjarne Tveskov Official Sets Space Space Police I Space Police I Sets Very Small Builds 

6831: Message Decoder

May 3, 2020July 29, 2023 Master Builder 6490 Views

Year Released: 1989
Designer: Bjarne Tveskov
Instructions
Bricklink

Back A
Back B
Back C
  • ← 918 – Back D
  • 6831 – Back A →

You May Also Like

6677 – Back C

June 8, 2023June 8, 2023 Master Builder

6909: Sonic Stinger with Promotional Mask

October 4, 2024March 22, 2025 Master Builder

Book 6000 – Page 54-55

November 7, 2021January 18, 2022 Master Builder

6989: Mega Core Magnetizer (Multi Core Magentizer)

September 15, 2019February 18, 2026 Master Builder

6827 – Back C

October 13, 2021May 18, 2023 Master Builder

6419: Rolling Acres Ranch

August 10, 2026August 10, 2026 Master Builder

EXPLORE MORE OFFICIAL SETS

535: Basic Building Set Tote Pack
Basic Large Builds Official Sets Universal Building Set 

535: Basic Building Set Tote Pack

May 15, 2023May 16, 2023 Master Builder

Year Released: 1990BricklinkInstructions

6373: Motorcycle Shop
Classic Town Medium Builds Official Sets Town Town Sets Traffic 

6373: Motorcycle Shop

January 6, 2022January 6, 2022 Master Builder
6399: Airport Shuttle
Airport Classic Town Different Box Versions Extra Large Builds Official Sets Town Town Sets 

6399: Airport Shuttle

February 24, 2023March 17, 2024 Master Builder
7256: Jedi Starfighter & Vulture Droid
Episode III Medium Builds Official Sets Star Wars Star Wars Sets 

7256: Jedi Starfighter & Vulture Droid

March 1, 2023May 12, 2023 Master Builder
1749: Paravane
Aquanauts Aquazone Aquazone Sets Official Sets Very Small Builds 

1749: Paravane

July 26, 2020July 26, 2020 Master Builder
6805: Astro Dasher
Classic Space Classic Space Sets Official Sets Space Very Small Builds 

6805: Astro Dasher

December 10, 2025December 10, 2025 Master Builder
5581: Magic Flash
Extra Large Builds Model Team Model Team Sets Official Sets 

5581: Magic Flash

January 2, 2024January 2, 2024 Master Builder
6397: Gas N’ Wash Express
Classic Town Extra Large Builds Gas Station Official Sets Town Town Sets Wrecker 

6397: Gas N’ Wash Express

July 14, 2021July 14, 2021 Master Builder
1843: Space/Castle Value Pack
Bonus/Value Packs Castle Castle Sets Official Sets Royal Knights Small Builds Space Spyrius Spyrius Sets 

1843: Space/Castle Value Pack

January 21, 2021September 13, 2023 Master Builder
5958: Mummy’s Tomb
Adventurers Adventurers Sets Desert Large Builds Official Sets 

5958: Mummy’s Tomb

October 27, 2019July 14, 2022 Master Builder
4750: Draco’s Encounter with Buckbeak
Harry Potter Harry Potter Sets Official Sets Prisoner of Azkaban Very Small Builds 

4750: Draco’s Encounter with Buckbeak

May 16, 2023May 16, 2023 Master Builder
5920: Island Racer
Adventurers Adventurers Sets Dino Island Official Sets Small Builds 

5920: Island Racer

July 26, 2020July 26, 2020 Master Builder
6257: Castaway’s Raft
Niels Milan Pedersen Official Sets Pirates Pirates I Pirates Sets Small Builds 

6257: Castaway’s Raft

June 6, 2022July 29, 2023 Master Builder
6903: Bug Blaster
Insectoids Insectoids Sets Official Sets Space Very Small Builds 

6903: Bug Blaster

October 4, 2024October 4, 2024 Master Builder
6940: Alien Moon Stalker
Classic Space Classic Space Sets Large Builds Official Sets 

6940: Alien Moon Stalker

September 12, 2019September 12, 2024 Master Builder
6512: Landscape Loader
Classic Town Construction Official Sets Town Town Sets Very Small Builds 

6512: Landscape Loader

May 10, 2022May 10, 2022 Master Builder

BOXES

INSTRUCTIONS

FAVORITES

MINIFIGS

About This Site

Logo
There were once pictures of additional LEGO® builds on the back of set boxes. Written on the boxes was typically something about the endless building possibilities, "Build any of these exciting models with this set!" There were no instructions for these alternate builds, until now.

Sets

  • Adventurers
  • Aquazone
  • BATMAN
  • Bionicle
  • Belville
  • Building Set with People
  • Castle
  • Duplo
  • Fabuland
  • Harry Potter
  • Holiday and Event
  • LEGOLAND
  • Model Team
  • Pirates
  • Space
  • Star Wars
  • Technic
  • Train
  • Town
  • Universal Building Set
  • Western
  • More Sets
  • Misc

Useful Links

  • Submit Instructions!
  • New Instructions
  • New Official Sets
  • New Alternate Builds
  • Minifigs
  • Very Small Builds (<35 pcs)
  • Small Builds (<100 pcs)
  • Medium Builds (<200 pcs)
  • Large Builds (<400 pcs)
  • Extra Large Builds (>400 pcs)
  • How BOTBB was Built

In Honor of 1526

The classic space set that never was.

Copyright © 2026 Back of the Box Builds. All rights reserved. LEGO® is a trademark of the LEGO Group of companies which does not sponsor, authorize, or endorse this site.