The Bob Semple tank was designed by New Zealand during WW2, intended to help defend against a potential Japanese invasion. A threat it may have faced was the Type 97 Automatic Cannon, firing the 20mm Type 100 Armour Piercing Round. The simulation shows what would happen if the round hit 2 different points of the corrugated armour.
The gap between the corrugated plate and main armour creates a simple type of spaced armour, which is known to be effective against AP bullets. This type of armour works via the outer layer shattering the core, making it easier for the main armour to stop the fragments. This theory was used for the Panzer III/IV Schurzen and on modern IFVs with applique armour.
As far as I know, the Bob Semple had the same armour layout around the whole tank (except areas without corrugated armour) so the simulation can be viewed as the Type 100 AP round hitting anywhere on the vehicle with a 10° horizontal angle.
For the simulation the hardness of the components had to be approximated, with the manganese steel being ~400BHN (possible after shot peening or heat treatment), the armour plate being ~300BHN, and the projectile being ~550BHN. It's unclear if this was the intended final armour layout, or just a placeholder until thicker armour plates could have been obtained.
Amazing thumbnail artwork from: @TanksEncyclopediaYT and WW2-history.fandom
![](https://s2.save4k.ru/pic/VyXzGsKIobk/mqdefault.jpg)