Skip to the card

Card 621 of 9992026-08-30 issue

Observed arrival · 2026-08-30

大人の復習ドリル: Geometry Problems for Grown-Up Brains

otonanofu.com Observed source
Editorial interest 78/100 Selection signal · not a rating of the site

A Japanese practice tool with 100 middle-school entrance-exam geometry problems, offering hints by drawing one line at a time on each diagram.

Landing page captured for the 2026-08-30 issue.

Field notes

The tool organizes a 100-question collection around diagram-based geometry, with separate difficult and ordinary sections. Its question types include shaded-region areas, circle and solid geometry, shadows, water depth, matchsticks, clock-hand angles, and counting diagonals or squares. The page describes a progressive hint system in which lines are added to a figure one at a time. It also identifies the project as version 1.6-26.8.29 and discloses AI-assisted generation.

Observed signals

Read the marks

Editorial observations of this landing page, not a rating.

OpenPublic substance visible
PrettyNotable craft visible
ProPolished or operationally mature
NicheUnusually specific use

One card from the complete issue

The Unserved Branch

223,571 arrived 1,000 judged 999 catalogued Enter the complete issue
otonanofu.com

Landing page observed 2026-08-30. The live site may have changed.