The goal is build the most powerful race car possible, as quickly as possible. To do this, each player seeks to get one of each of the 6 Parts needed to build a race car.
The Parts includes Fuel (the Raindrop), Pistons (the Hammers), Battery (the Circles - they are "atoms" here, and thus electricity), a Driveshaft (the Bricks), Tires (the Cog), and a Gearshift (the Arrow). To build a functioning car, one of each Part must be present.
However, the goal is not simply to complete a car, but to build the most powerful car. The part's power is determined by the number on the card. The higher the number, the more powerful the part. The more powerful the parts, the more powerful the car.
Shuffle the cards.
Deal each player 6 cards.
Place the remaining cards in a single stack, face down in the midst of the players. This is the "Parts Deck" (Draw Deck).
The top card is removed from the deck and placed next to it, face up, to begin the "Scrap Heap" (Discard Pile).
Players take turns either (a) drawing a card from the face-down Parts Deck, or (b) taking the top card from the Scrap Heap. The player then either discards a card to the Scrap Heap and ends their turn, or "Pulls up the the Starting Line". The next player begins their turn.
Pulling up to the Starting Line means discarding one card from their hand - and then placing their cards, face down on the table and declaring "Start your engines!". Once a player is at the starting line, they are no longer drawing or discarding.
The player who pulls up to the starting line first gets 3 bonus points added to their vehicle's power rating. The second player gets 2 bonus points. The third gets one. After the 3rd player, there are no more bonus points.
Players can continue to take their turns as long as there are at least 2 players not yet at the Starting Line. When there are only 2 players left, the final player only gets one turn after the other player pulls up to the starting line.
If the final player does not have a completed vehicle (meaning one of each part) in their hand. They are out of this race.
If the Parts Deck is ever exhausted during a race, the Scrap Heap is turned over, shuffled, and then becomes the Parts Deck. The top card is turned over to start the new Scrap Heap.
After every player is at the starting line, they declare (in order of pulling up to the starting line) the point total for their vehicle. This is calculated simply by adding all the numbers on their parts, and whatever "Pole Position" bonus they may have received by being 1st, 2nd, or 3rd to the starting line.
The player with the highest score wins.
Advanced - "Race Circuit": Edit
If players want to play more than one race, they can play a "Race Circuit" - which consists of a number of races (hands) played in a given time.
Scoring for overall winner of the Race Circuit (game) would be determined based on the position of players in each race (hand). This is calculated by giving each player points based on their position in each race.
The score is based on the number of players per race, with the first place racer in each race receiving the same number of points as players in the race. (Players who do not complete their vehicle in a given race are still counted towards that total.)
So if there are 4 players in a race, the player who got first place in that race would receive 4 points, the first runner up (second place) would get 3 points, the next player would get 2 points, and the final racer would get 1 point. If a player is unable to complete their vehicle - they receive 0 points for that race.
This can be calculated per race, in case the number of players changes throughout a race circuit.