Wednesday, July 8, 2020

Hanging in Suspense - PackTIC V

PackTIC V by Andrew CrowellRecently, while I was on the phone, I pulled out the pieces of PackTIC V to keep my hands busy.  Does anyone hold a phone to their ear anymore?  Before I hung up, I had a complete 4x4x4 cube sitting on the table next to me.  Needless to say, I found this one easy and much easier than the other ACROSTIC puzzles that are rated as difficult.

Is PackTIC V really easy?  That’s not as easy to declare as you would think.  There is a tendency to equate the amount of time it takes to solve a puzzle with how difficult it is.  If you do enough of these, probabilistically, you’re eventually going to get lucky on making initial guesses for piece placements.  Many puzzlers have quickly solved a puzzle and declared it to be trivial only to be challenged in subsequent attempts.  Of course, the more puzzles you do, the luckier you are, and I’ve done quite a few of these TICs.

PackTIC V Pieces on a Tensegrity StructurePackTIC V was designed by Andrew Crowell and my version was 3D printed by Andrew.  It consists of 6 navy blue pieces that have to be inserted within a gray frame to make a cube with no visible voids on the exterior.  6 pieces is a lot for this type of puzzle and usually makes finding where the 6 pieces belong within the frame the major challenge.  However, for PackTIC V, I discovered where the pieces went rather quickly.

The predominant effort of solving this puzzle is getting the first 3 pieces in the frame.  The 4th piece requires a small rotation to place it in the frame and the remaining 2 are filler pieces that can be added or removed in a single move.

PackTIC V and Tensegrity StructureInserting any 2 of the first 3 pieces within the frame is trivial and when adding the 3rd, the other 2 always seem to get in the way.  Getting them in place requires determining the correct order of insertion and the rotations required to accomplish it.  All 3 pieces need to be rotated in the process.  Unlike some of the other ACROSSTIC puzzles, the rotations for PackTIC V are not that complex.  However, I did benefit by having thin fingers to accomplish one of them.  If you have a small version of this puzzle and large hands, beware.  Finding and executing this rotation is the hardest part of the solve and hidden pretty well.

The stand used to display the PackTIC V pieces is a tensegrity structure.  These have become popular lately as self-quarantining people are looking for things to do.  This one was made from STDs (yes, that’s standard tongue depressors) and string.  A side effect of the current pandemic will be a plethora of these homemade tensegrity structures.

This is the 7th post of the monthly Andrew Crowell Rotations and Obstructions Series - Turning Interlocking Cubes (ACROSTIC).  You can find the prior posts of the series here:


  1. So you built a tensegrity platform while on the phone. That's pretty good. And what about the PackTIC V again? -Tyler.

    1. Too easy for you. You could probably create a tensegrity structure with the PackTIC V pieces while on the phone.