Reverse Engineer

Mana cost: {3}{U}{U}
Type: Sorcery
Set: Aether Revolt #42 (uncommon)
Price: $0.20 USD

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Draw three cards.

Reverse Engineer has 7 printings, first in Aether Revolt (2017). EDHREC ranks it #8,038 among Commander cards. It appears most in Gimbal, Gremlin Prodigy decks (1,246 on EDHREC). 2 public decks on TCG run it. It has 8 official rulings.

Legality

commander: legal
legacy: legal
vintage: legal
pauper: legal
modern: legal
pioneer: legal
standard: not legal
brawl: legal

Public decks that run Reverse Engineer

Exquisite Invention - Commander 2018, led by Saheeli, the Gifted
Tinker Time - March of the Machine Commander, led by Gimbal, Gremlin Prodigy

Commanders that run Reverse Engineer most

Deck counts from EDHREC.

Often played with Reverse Engineer

Cards that show up in the same decks on EDHREC.

Rulings

2018-07-13: Improvise doesn't change a spell's mana cost or mana value.
2018-07-13: When calculating a spell's total cost, include any alternative costs, additional costs, or anything else that increases or reduces the cost to cast the spell. Improvise applies after the total cost is calculated.
2018-07-13: Improvise can't pay for {W}, {U}, {B}, {R}, {G}, or {C} mana symbols in a spell's total cost.
2018-07-13: Tapping an artifact won't cause its abilities to stop applying unless those abilities say so.
2018-07-13: Equipment attached to a creature doesn't become tapped when that creature becomes tapped, and tapping that Equipment doesn't cause the creature to become tapped.
2018-07-13: If an artifact you control has a mana ability with {T} in the cost, activating that ability while casting a spell with improvise will result in the artifact being tapped when you pay the spell's costs. You won't be able to tap it again for improvise. Similarly, if you sacrifice an artifact to activate a mana ability while casting a spell with improvise, that artifact won't be on the battlefield when you pay the spell's costs, so you won't be able to tap it for improvise.
2018-07-13: When using improvise to cast a spell with {X} in its mana cost, first choose the value for X. That choice, plus any cost increases or decreases, will determine the spell's total cost. Then you can tap artifacts you control to help pay that cost. For example, if you cast Saheeli's Directive and choose X to be 3, the total cost is {3}{R}{R}{R}. If you tap two artifacts, you'll have to pay {1}{R}{R}{R}.
2018-07-13: Improvise can't be used to pay for anything other than the cost of casting the spell. For example, it can't be used during the resolution of an ability that says “Counter target spell unless its controller pays {3}.”