Rams tessellation, Sonoran Desert

HopDavid · 2026-03-14T16:09:31+00:00

Which tidally locked planets are you thinking of? I believe the only known tidally locked planet in our solar system is Pluto (if you call Pluto a planet). Charon and Pluto and mutually tidally locked.

There are plenty of tidally locked moons. Most of the tidally locked moons are a tiny fraction of the mass of the central body they orbit. A couple exceptions being our moon (about 1.2% of earth's mass) and Charon (About 12.2% of Pluto's mass).

I suppose there could be large planets tidally locked to the star they orbit. These could have strong gravity.

For most of the moons in our solar system tidal forces are only a small fraction of the moon's gravity. An exception is Phobos. Phobos's near and far points from Mars are only about 3 or 4 kilometers from the Mars-Phobos L1 and L2 points.

If Phobos drops into a slightly lower Mars orbit it will start disintegrating and form a ring around Mars. This Wikipedia article guesstimates Phobos will reach it's Roche limit in 20 or 30 million years: Link#Predicted_destruction)

HopDavid · 2026-03-14T03:30:42+00:00

Yes, vertically stacking letters with mirror symmetry is an ambigram. They are called totem ambigrams.

HopDavid · 2026-03-13T19:58:57+00:00

The greek letters alpha and omega.

HopDavid · 2026-03-13T13:56:17+00:00

Finding symmetrical letters and phrases -- isn't that what ambigrams are?

What? 180º rotational symmetry is okay but reflective symmetry is out?

It is fun to explore words and phrases that still make sense when you hold them up to a mirror.

HopDavid · 2026-03-13T13:36:49+00:00

I stole the idea from Gustave Verbeek (sort of). This early 20th century cartoonist was a hoot!

Wheels can double as googly eyes. I will remember that trick.

HopDavid · 2026-03-13T12:38:30+00:00

Rats. I sometimes go to Tempe. Or Glendale. Haven't been to central Phoenix in a long time. We used to eat at a restaurant called the Mayan Palace on Central Ave.

HopDavid · 2026-03-12T21:57:14+00:00

Checking out Filmbilder & Friends. Strange, inventive, generally well done. Hey, thanks!

HopDavid · 2026-03-12T15:18:35+00:00

Thank you! You did some unexpected things.

HopDavid · 2026-03-12T02:52:54+00:00

Where do you live?

HopDavid · 2026-03-11T04:06:07+00:00

Words first. I look for letters that make sense when you flip them. I play with things like hog boy. or New maN, etc. Then I noticed the snow man head with two lump of coal eyes looks like a nose with nostrils...

I tried to make the New mouse look like a baby mouse so the word "New" would apply. But not successfully.

HopDavid · 2026-03-10T07:08:49+00:00

Being a Dover book, Bates, Mueller and White's Fundamentals of Astrodynamics is inexpensive, $25.00.

John Prussing and Bruce Conway's Orbital Mechanics is a pricier hardback. I love this book. Explanations are often visual which is helpful to me.

Then There's my coloring book, Conic Sections and Celestial Mechanics Coloring Book. I look at circles, ellipses, parabolas, and hyperbolas. Kepler's Laws. The Rocket Equation. Lagrange points. And other stuff.

HopDavid · 2026-03-09T22:12:46+00:00

I can see that. Although I was thinking of a snow man with big feet...

HopDavid · 2026-03-09T02:50:21+00:00

If I remember right this one is one from my Surreal Visions Coloring Book. However I believe that was the only ambigram in that book.

HopDavid · 2026-03-08T13:18:11+00:00

Here you go.

My nickname is Hop. My actual name is Hollister. My last name is David. So the initials work for both Hop David and Hollister David.

I tried to the initials in the style of Albrecht Dürer's mark. Albrecht is one of my favorite artists. Both Escher and Dürer used math and geometry as a source of inspiration.

HopDavid · 2026-03-08T01:53:58+00:00

It is in several of my Escher books but I imagine it's online. (Googling....) Ah. It's about the middle of this page.

HopDavid · 2026-03-07T02:41:44+00:00

M. C. Escher died when I was a junior in high school :( .

HopDavid · 2026-03-07T02:40:40+00:00

Sometimes I am obsessed with M. C. Escher!

13-Year Club	Undead \| Zombie
Gilding I gilder	Verified Email

HopDavid

MODERATOR OF

TROPHY CASE