Engineering Sandbox lab ยท blockchain systems
Edit a block, watch the chain break, then mine it back into coherence.
This lab is best when you treat the chain like a live dependency graph. Change the earliest payload, watch downstream hashes and validity states fall out of sync, then repair the first block so you can see why one successful mine is not enough to fix the whole system.
Edit the data in block 1, look at block 2's previous-hash field, then press Mine on the first block only. The fastest way to understand the chain is to watch which state repairs and which state stays broken.
What to observe
- 1Tamper early. Change the first block so the rest of the chain has to react to it.
- 2Track propagation. Compare the current hash with the next block's previous-hash field.
- 3Repair locally. Mine the edited block and notice that downstream blocks still need work.
Why this matters
The point of the demo is not just to produce a valid-looking hash. It is to see how immutability emerges from linked dependencies: one edit changes one hash, which invalidates every later reference that trusted it.
Read the states
- 1Green blocks are locally valid again after mining.
- 2Red blocks still trust an older previous hash and need their own repair step.
- 3Scroll right to keep following the cascade into later blocks.
Keep going
The row is horizontally scrollable because the later blocks matter. Use the distributed view when you want to compare competing peers, or jump into keys and signatures once the chain state feels concrete.