On the Subject of Buddy Bidding

Nothing like being an auctioneer

On the module there is a display showing Buddy in one of five colors (Red, Green, Yellow, Blue, or Pink), a keypad with a red delete button and a green enter button, left and right arrow buttons, and a credit card. In order to solve the module you need to successfully bid on 3 items that you want. If you buy an item that you do not want, fail to buy an item you do want, or spend too much money, you will receive a strike.

Step 1: Your Balance

You will have a specific amount of money that you can spend on items. To determine how much money you have, follow this formula:

Balance = ((C[S[3]] + 1) * (C[S[6]] + 1) * (C[D+10] + 7 - D)) % 600 + CVV

See the Formula Key Appendix to compute it.

Step 2: Your Wanted Items

Next, you have to determine which items you want. But first, if there is a lit BOB indicator, exactly 3 batteries, and a letter from “BUDDY” in the serial number, you are actually Buddy’s good friend Bob here to give a donation. Simply bid all of your balance on Buddy to solve the module. Otherwise follow the steps below.

When determining a Wanted Item in the Products Appendix, if you want an item that is already a Wanted Item, you actually want the next non-Wanted Item in reading order.

Item 1:

You need to find the letter corresponding to Item 1 in the table below. To find the row and column use the formulas below. See the Formula Key Appendix for information on the meanings of the abbreviations. Use this letter in the Products Appendix to find your first item.

Column Number = (C[O] - 36) % 18 || Row Number = (C[E] - 36) % 18

	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17
0	C	A	F	B	H	G	I	B	D	E	F	B	G	F	H	H	G	B
1	B	J	G	B	D	G	B	A	J	I	H	I	C	E	H	B	F	D
2	J	E	J	C	G	D	I	F	E	D	G	C	C	A	C	D	E	A
3	A	I	H	H	E	I	G	I	C	B	J	E	I	J	I	A	H	J
4	B	F	F	H	B	H	C	C	D	J	A	D	J	E	F	E	H	H
5	A	C	F	J	A	E	D	H	H	E	C	H	J	G	E	C	I	H
6	C	I	A	J	B	F	C	G	C	F	I	I	H	F	A	D	J	H
7	D	B	I	E	F	B	C	J	E	D	B	D	G	B	A	C	A	G
8	D	J	J	F	G	F	B	A	I	D	E	G	G	A	E	E	F	D
9	A	J	C	C	A	G	I	B	D	F	D	E	H	F	B	C	G	F
10	E	E	C	E	F	B	G	C	I	C	J	C	D	B	B	F	I	F
11	F	C	D	F	H	E	F	C	G	F	A	A	A	H	E	J	C	C
12	D	F	G	H	A	J	A	E	H	E	D	C	I	I	H	C	G	G
13	D	A	J	G	A	A	I	E	C	B	C	G	C	E	G	B	D	I
14	F	D	J	B	E	C	E	F	G	H	C	G	A	B	I	F	D	B
15	B	I	H	A	I	I	C	E	B	G	J	E	I	G	G	E	H	I
16	H	C	D	E	B	I	E	E	B	J	C	C	A	F	J	I	D	I
17	A	G	H	I	E	D	J	G	J	J	E	G	F	C	D	H	F	H

Item 2:

Item 2 can be found by taking the digital root of your balance multiplied by a different number, based on the color of Buddy (Red = 3, Green = 7, Yellow = 13, Blue = 17, Pink = 19), all modulo 10.
Convert this number into a letter (A0J9) and find the item associated with that letter in the Products Appendix, this is your second item.

Item 3:

To find your third wanted item, use the table below. Use the company of the credit card as the column, and the first rule that applies as the row. After that, find the item associated with the letter in the Products Appendix for the final time.

Company Names → Rules ↓	Koopa Cash	Royalcard	Purple Banking
If there are 4 or more indicators:	I	B	D
If the number of batteries is the same as C[10]:	E	C	H
If C[E] is less than 20:	D	B	I
If C[O] is greater than 40:	A	B	J
If there is a Parallel or Serial port:	H	H	F
Otherwise:	E	F	G

Bidding Functionality

After you have determined your items and how much you can spend, it’s time to start bidding for them! Press the green enter button to open the auction house. Specific information about bidding on this module can be found below.

• After 1 minute of no opposing bids on an item, that item will be sold to the highest bidder.
• The starting bid for each item is 25 coins.
• If an item has no bid, the text color of its cost will be blue; if you have the highest bid, it will be green; otherwise if a module bidder has the highest bid, it will be red.
• Some items will go unsold that day by default (including wanted items), but will have an opposing bidder if you choose to bid on them.
• For your wanted items, opposing bidders’ maximum amount they can bid up to will always sum to (your total balance * 0.01 + 30) less than your total balance.
• Opposing bidders will bid in coin intervals of 5-20 (unless it would go over their maximum), and in time intervals of 10-35, both at random.
• You can bluff by bidding on items you do not want in order to reduce the maximum of a bidder on a random item that you do want. This is risky because if no bidder on the random item you bid on wants to pay that price, you will instead pay that price and receive a strike.
• If you accidentally purchase an item you do not want this way, the maximums of the opposing bidders on items you do want will still go down accordingly to make it possible to solve without striking again.
• Once you purchase 2 items, you can safely dump the rest of your balance into the last item to solve after 1 minute.
• At 1 second left of bomb time, the module will sell each item to the current bidder.
• If you fail to purchase any Wanted Item, the bomb will blow up.

Appendix: Formula Key

• C[#] = The digit of the credit card number at position # (1-indexed)
• S[#] = The value of the serial number character at position # (1-indexed) (A10Z35)
• D = The number of distinct characters in the serial number
• CVV = The three numbers on the back of the credit card. Interact with the credit card to flip it over.
• X[O/E] = Add all digits in odd/even positions of the number X (ex: C[O] = sum of digits in odd positions of the credit card number)

Appendix: Products

Below is the table of products available for auction and their associated letter.

A		B
C		D

E		F
G		H
I		J