# A twisted enigma

Is it a miniature meal? An old calculating device?

The secret message is

Slider

The model appears to be

DNA - with colors mapping onto nucleic acids

Searching for different possible mappings...

One of the possible mappings, blue->T, yellow->A, green->C, red->G, allows translating the sequence into the word SLIDER. Not only that, it translates the same forward and backward (5' to 3' and vice versa), making it fully palindromic at the protein level, even though the DNA isn't a perfect palindrome.

The other mappings don't have an obvious translation.

Finally,

Slider can refer to a small hamburger (miniature meal) or a slide rule (old calculating device), matching the extra clues :)

• Well done, 5 out of 5 solved! You didn't use the same mapping I did, but it just goes in another direction. If anyone wants all the gory details of how I designed the puzzle, I've published it on GitHub. (Complete spoiler, obviously.) – Don Kirkby Dec 3 '19 at 4:21

Not sure if I'm missing the actual puzzle, but this seems to be

a model of a double helix

• That's the first level, yes. There's more that makes it special. – Don Kirkby Dec 1 '19 at 22:14
• @aml rot13(Na "byq pnyphyngvat qrivpr" jbhyq or na "nonphf", juvpu vf n fvk yrggre jbeq. Nal vqrn ubj gung zncf gb gur frdhrapr?) – Darrel Hoffman Dec 2 '19 at 20:21

If I'm right it is

DNA

We can see it by noting that

the color always match green with red and Blue with yellow. Same as matching aminated acid in DNA

• Everything you've said is right, but that's only the first out of five things to solve. What makes the example in my picture special? – Don Kirkby Dec 2 '19 at 3:40
• I knew it was too simple for Puzzling! SE :) – Alain Remillard Dec 2 '19 at 15:43

# Wrap-up: The Making Of A Twisted Enigma

This is not a solution to the puzzle, but provides notes from its poser. This type of answer has been approved by the community.

Caution: This post may contain spoilers.

### Inspiration

I work as a software developer, and specialize in bioinformatics to help HIV/AIDS researchers. A lot of the work involves viral genetic sequences, and converting from nucleotides to amino acids. This summer, I found the boardgame Splice in a thrift shop. I wondered if I could use the letters for amino acids to form some kind of word game, and display it with the game pieces.

### Creative steps

I work as a software developer, and specialize in bioinformatics to help HIV/AIDS researchers. A lot of the work involves viral genetic sequences, and converting from nucleotides to amino acids. This summer, I found the boardgame Splice in a thrift shop. I wondered if I could use the letters for amino acids to form some kind of word game, and display it with the game pieces. I decided that encoding a word would be fun, and then the idea of palindromes restricted the search space.
I wrote the puzzle.py script to search through the dictionary, and look for sequences that encode a word in both directions. It highlights sequences where both directions encode the same word. After I did that and found that there were several words that worked, I had the idea to look for sequences where the amino acid sequences were the same in both directions, but the nucleotide sequences weren't. SLIDER was the only word in my dictionary that worked, so I decided to go with that.

### Logistical steps and resources

Once I had the sequence I wanted, I discovered a couple of problems with my Splice game. First, the helix is left handed, while most DNA molecules are right handed. Luckily, I could fix that easily by flipping the photograph. Harder to fix was the fact that the nucleotide pairs in the game didn't connect the colours according to the standard DRuMS colour scheme. I think it's very strange that they used the standard colours, but didn't pair them correctly. Considering that and the wrong handedness, I would guess that they didn't ask any biologists before they manufactured the game. I briefly considered taking apart the pairs and regluing them, but instead I decided to fix it by adjusting the colours in the photo. With some good advice from Mike O'Shaughnessy, I wrote the swap_colours.py script to swap the blue and red, as well as flip the photo. Hopefully, nobody noticed the photo manipulation, but if you look at the edges of the blue and red sections, you can see it.

### Takeaway

I was worried that this puzzle would be too hard, because it required a lot of specialized knowledge: the standard colour scheme for nucleotides and the translation table for amino acids. I made sure that the information was reasonably easy to find on line, but I still thought it was a pretty big ask. I was pleased that several people made some general guesses, and tmpearce solved it within a day.

The detailed things I was looking for in a solution were:

1. It's DNA. 2. There are six codons in the sequence. If you've forgotten your high school biology, DNA is made up of two chains of nucleotides, and codons are groups of three nucleotides. Each codon is a code for an amino acid, and each amino acid is represented by a letter. The sequence in the picture could translate to a six-letter word. 3. The colour scheme is the closest I could find to a standard: the DRuMS colour scheme. The nucleotides A, C, T, G are represented by blue, red, yellow, and green with the mnemonics Azure, Crimson, Tweety bird, and Green. Together with the codon table you could then decode the sequence that starts with yellow, red, green as "SLIDER". That matches a couple of the clues to let solvers know they're on the right track. 4. Now it gets more subjective. What I was looking for was for the solver to notice that the two chains encoded "SLIDER" in opposite directions. 5. The final level was to notice that although the two chains encoded "SLIDER", the actual nucleotides were different. Each amino acid can be encoded by more than one set of nucleotides.

That's all the gory details. Leave a comment if you can find other items like this one, or if you'd like to collaborate on designing a puzzle. If you enjoyed this, you might like my Donimoes collection.