"Visiting Flatland" by benchen71

[woozy]

4. The puzzle title refers to a 19th century book about a 3D shape visiting a 2D world by slowly passing through it.

.... and how the inhabitant of the 2D could only view the part of the 3D shape that was intersecting the 2D world... and then only from the side

This was a very clever puzzle.

[CromsFury]

Snuck into the castle last night. Crosshare confirmed it this morning.

[whimsy]

First nudge finally steered me away from tremendously over complicating --

Thanks for a puzzle that kept me quite busy, Ben, and also refreshed my memory of a book my son and I first read together nearly 25 years ago.

[benchen71]

Lots more solvers! Yay!!

vandono
markhr
SJMcK
Dow Jones
Chas
CromsFury
Anita
DIS
Yash Pujara
Bbaack
Laura M
LindaPRmaven
whimsy
Chaddog

We're up to 30 now.

[rjy]

Turned blue from all the time spent in the moat, but the first nudge finally pulled me out, not without further dog-paddling. Very clever puzzle, Ben, and appreciate the artful nudges that still left a challenge. Cheers all!

[benchen71]

Monday morning here in Oz, and that means it's time for the answer reveal. But first the last of the solvers to make it across the line:

Account
rjy
Carolyn

That brings us to a grand total of 33. Well done, everyone!

[benchen71]

And here's the answer...

This meta would have been a lot easier for those of you familiar with Flatland. In this book, an inhabitant of a 2-dimensional world is visited by a 3-dimensional object, the Sphere. From the Square's perspective, the sphere's appearance begins as a dot that quickly becomes a circle that increases in size before then decreasing in size back to a dot that then vanishes. What has taken place? The sphere has passed through Flatland.

So in this meta, there are six 3-dimensional objects that are in the process of visiting Flatland. But where is Flatland? Well, it's the only column in the grid that passes through all 3-dimensional objects: the central column. This is the SEAM or "line" referred to in 10 D: a 2-dimensional plane seen end on so that it becomes a 1-dimensional line. Once you've found Flatland, you can see that the letters in the 3-dimensional objects that are currently intersecting with Flatland spell out SPHERE.

[benchen71]

By the way, here's the first review of the 1st Pre-release MOAT pack, courtesy of Al Sisti. Thanks for the kind comments, @Al Sisti!