https://scription.typepad.com/

Patrick Ng seems to be the inventor of a chronodex visual planning system. His website has half yearly printable planner inserts for Midori's Traveler's Notebooks.

One of his downloadable templates reads:

Chronodex ideas and notations are copyrighted, it is free for personal use, please contact Patrick Ng (patrickng@mac.com) for commercial usage.

Examples of chronodex layouts on his website show his uses which also seem to include some sketchnoting usage as well.

https://www.aliexpress.us/item/2251832721946110.html?gatewayAdapt=gloMsite2usaPcglo2usa4itemAdapt

A 12 and a 24 hour variation

via https://www.reddit.com/r/notebooks/comments/1nrtcm/anyone_else_using_scription_chronodex/

https://www.alibaba.com/product-detail/timeline-brass-hand-account-seal-with_1600086782499.html

http://jolarsenburnett.blogspot.com/2012/01/patrick-ngs-chromodex-diary-system.html

She indicates she has an Adobe file, but I see no immediate evidence of it. Apparently waiting on permission from Patrick Ng?

https://www.flickr.com/photos/annettechung/11451796944/in/pool-1804503@N25/

Jo Larsen Burnett has a variation of Patrick Ng's chronodex: http://jolarsenburnett.blogspot.com/2012/01/patrick-ngs-chromodex-diary-system.html

https://www.flickr.com/photos/moleskineart/7029712939

Scription Chronodox is a Beautiful, Printable, Freeform Weekly Planner for the New Year by Adam Dachis on 2011-12-29

https://stationerymanor.com/products/kokuyo-mo-series-round-stencil-template-97018

Kokuyo has a circular stencil/template (WCN-CDTAS13), which one presumably holds down in the center and then uses the various slots with a pen/pencil to circle around to make their own custom chronodex stencil outlines.

It doesn't take a genius to see how Baum-kuchen could potentially use such a tool or stamp to make a branded chronodex that also might suggest the circular layers of an actual Baum-kuchen cake.

https://www.yesstyle.com/en/tcuc.USD/coc.US/info.html/pid.1063008517?cpid=1063008516&googtrans=en

In stock version of chronodex stamp and similar bullet journal stamps.

https://www.yesstyle.com/en/ninas-house-chronodex-stamp/info.html/pid.1051531212

Naturally, someone has turned the chronodex into an inkable stamp.

https://tex.stackexchange.com/questions/688083/replicating-a-chronodex-in-tikz

Someone has programmed up most of a printable chronodex in TikZ for LaTeX!

https://www.amazon.com/Patrick-Chronodex-Time-Management-Planner/dp/B08CMYCF6V

Patrick Ng is selling a chronodex planner on Amazon.com

https://erinflotodesigns.com/collections/metal-stencils/products/bullet-journal-monthly-circle-tracker-stencil-habit-tracker-stencil-unique-design-stencil-cleaning-tracker-stencil

Erin Floto has a metal stencil for a chronodex circular design for use in bullet journals. It's a form of circular calendar with the inner circle containing space for daily, bi-weekly, weekly, monthly and longer time horizons with succeeding rings of the circle containing space for data related to the inner categories. Some of the exterior rings also include numbered squares representing days of the month or week on which a task should be done or for which a habit on an interior part of the circle might be tracked.

The chronodex, a portmanteau of chrono (time) and index, idea is fairly simple, but can be quite complex. For actual use, one may need to be able to spin the visualization around to read and understand it.

Other stencils with habit trackers, etc: https://erinflotodesigns.com/collections/metal-stencils