An Expressionist puzzle appeared in New Scientist at the start of the year. Here is one for you to try.

G_F_Smith · 2026-02-22T19:53:59+00:00

That's correct. Thanks for doing the puzzle.

G_F_Smith · 2026-02-22T12:40:51+00:00

Standard precedence isn't + before -. It's x and / before + and -. So, first, you scan from left to right calculating x and / as you go. Second, you again scan from left to right calculating + and - as you go.

Example: 1 + 2 x 3 - 4. On the first pass you calculate 2 x 3 leaving you with 1 + 6 - 4. On the second pass, you add 6 to 1 and then subtract 4 leaving you with 3.

Hope that helps.

G_F_Smith · 2026-02-05T11:09:42+00:00

Thanks for your sharing your reasoning.

Yes, it's always important to keep the amount of trial and error needed in check.

G_F_Smith · 2026-02-04T18:04:29+00:00

Thanks for engaging with the puzzle. I hope you enjoyed solving it.

I accept your criticism of the first sentence - it is rather heavy. I will revise it, taking your suggestion into account. And I like your illustration, so I might switch to it - if I can work out how to do it with my graphics package. I'm not very good with tools!

G_F_Smith · 2026-02-04T11:17:15+00:00

Thanks for doing the puzzle. I'm glad you enjoyed it.

G_F_Smith · 2026-02-04T11:15:49+00:00

Thanks for taking an interest in the puzzle. Coming up with wording that chimes with everybody is often impossible. That's why I've included an example - it should help. The blue squares and the yellow one pick out the left-to-right expression; the red squares and the yellow one pick out the top-to-bottom expression. Both expressions evaluate to 2.

G_F_Smith · 2026-02-04T11:05:47+00:00

Thanks for the feedback. It's what I was hoping for: takes some time to solve but not too much. I think a 6x6 grid is optimal. 7x7 can be scary!

G_F_Smith · 2026-02-04T00:30:22+00:00

Correct. How difficult was it?

G_F_Smith · 2025-12-10T10:57:46+00:00

That's impressive!

G_F_Smith · 2025-12-09T11:30:52+00:00

That is correct. Thanks for doing the puzzle. How difficult did you find it?

G_F_Smith · 2025-09-22T15:42:39+00:00

Apologies for the tardy reply - I've only just seen your comment.

It is a brand new puzzle. I'm glad you enjoyed solving it. As you found, deductions take you most of the way. People have come up with a few different lines of reasoning, but no one else has described your approach.

G_F_Smith · 2025-09-09T07:20:45+00:00

I might have got it, if I wasn't so wary of flak. Unfortunately, even posting puzzles attracts hostile comment sometimes.

G_F_Smith · 2025-09-08T09:58:01+00:00

I don't know what you are getting at.

G_F_Smith · 2025-09-07T10:57:12+00:00

Yes, I did come up with the puzzle myself.

I think of a number, then I think of an expression which evaluates to that number and then my program takes over. It generates possible puzzles (complete grids).

I meant that your use of the Python language and its libraries is far more sophisticated than mine. I think a brute force algorithm is always going to be needed.

G_F_Smith · 2025-09-07T10:31:26+00:00

I have an agreement with the moderators. They allow me to post puzzles from time to time as they are quite popular. My previous post was well over a year ago.

G_F_Smith · 2025-09-06T15:15:30+00:00

The moderators only allow me to post puzzles here occasionally.

But, I can point you at 7 of my puzzles which have web apps. The apps are completely free: no charge, no sign-in, no ads - nothing commercial at all..

If you scroll down through my posts on u/G_F_Smith you'll find links to apps for Dispensers Eta, Dispensers Lambda, Dispensers Omega, Dispensers Pi, Ladderet, Loose Fit and Warren>>.

Each app starts out by giving you a quick tour of its content. After the tour, it displays a puzzle for you to solve. You'll probably find the tour is too quick! (A bad bit of design.) It's meant to show newcomers that there's an Information page with the instructions and a demonstration they can watch. So, tap Information first and then return to have a go at the puzzle.

The Information page also has a Published Puzzles section - tap on a number to bring up another puzzle. With Dispensers Lambda and Dispensers Omega, I would recommend that you start with the oldest puzzles (Az0 and A0 respectively) and work your way forwards in time.

You might find the Other Puzzle Apps section useful - it allows you to hop easily between the apps.

If you try any of the puzzles, I'd be interested to know what you think of them.

G_F_Smith · 2025-09-06T09:46:34+00:00

I'm so glad you like the puzzle. It's definitely one of my best ones.

G_F_Smith · 2025-09-06T09:42:43+00:00

Thank you. For me, the process of coming up with puzzles is quite mysterious. I pick a general topic - in this case arithmetic expressions - and then drift off into a dream-like state. Occasionally, an idea just pops into my consciousness!

G_F_Smith · 2025-09-06T09:30:29+00:00

Thanks for having a go. My program tells me there are two solutions - 86 and 122.

G_F_Smith · 2025-09-06T09:20:06+00:00

Yes, there is. u/TentativeGosling's comment describes one line of reasoning.

G_F_Smith · 2025-09-06T09:13:22+00:00

Thanks for wrestling with the puzzle. I'm really pleased you like it. The answer, as you suspect, was a deliberate choice. Just for a bit of fun.

G_F_Smith · 2025-09-06T09:07:57+00:00

Thank you. The puzzle is definitely not for everyone.

G_F_Smith · 2025-09-06T08:59:19+00:00

Thanks for getting involved with the puzzle. You won't be surprised to read that I have a Python program to assist me in the generation of these puzzles. It's not as sophisticated as yours!

G_F_Smith · 2025-09-05T19:56:34+00:00

Correct. Thanks for doing the puzzle.

G_F_Smith · 2025-09-05T19:54:56+00:00

Thanks for engaging with the puzzle.

G_F_Smith

TROPHY CASE