Order now: book Vitamin G containing a collection of 100 beginner-level puzzles, focusing on basic geometric figures such as circles, triangles, and squares. amazon.com/Vitamin-100-whole…

In square ABCD (side 1), a quarter-circle arc centered at A passes through B and D, and a semicircle is drawn on diameter AD. Line BP from B is tangent to the semicircle at T and meets the arc at P. What is the ratio green : orange? mirangu.com/the-tangents-sha… By Google Gemini.

Dear geometry lovers, After almost 5 years, we end puzzle production. We both intend to move on to new activities. Thank you all puzzlers for your interest and beautiful solutions. Please feel free to visit our archive at mirangu.com. All the best, Marshall and Rik

Three discs have one 3-way common point on their boundaries. Where do the red rays intersect? How are the points of intersection related to the common boundary point? mirangu.com/when-worlds-coll… By @MarshallWBuck

Three circles (two with centre) and four line segments. Prove that, if the small circle is orthogonal to both wheels, then the wheels are also orthogonal to each other. mirangu.com/the-odd-bicycle/ Inspired by @ChrisWildhagen

A triangle cut by a line and four parallel line segments. Prove that green = red. mirangu.com/above-the-line/ Inspired by @ChrisWildhagen

A circle with its centre and three triangles consisting of chords and radii. Express area X in terms of A, B and α. mirangu.com/kazakov-triangle… Inspired by @kazakov_yu

A square, a rectangle and two semicircles, one of which is centered in the shared vertex. What is yellow : blue? mirangu.com/unity/ Inspired by @eylemboss0306

During one step every internal polygon rotates to the next position along its outer polygon, merging two green sides. How many full turns are made by the innermost triangle before the entire configuration returns to its initial state? mirangu.com/flower-of-gears/ By @MarshallWBuck

Two concentric quarter circles and a square. What is purple : red? mirangu.com/the-gakopoulos-p… Inspired by @TGakopoulos

Two circles, a common tangent and several line segments. Prove that the red line segments are parallel. mirangu.com/velocipede-v/

A regular hexagon shares a side with a regular nonagon. What’s the angle α? mirangu.com/sixtynine/

A rectangle inside a square. What fraction is yellow in terms of x? mirangu.com/brick-oven-ii/

The left wall of a rectangular pit can slide frictionlessly along the floor. An inward force of F is needed to maintain the position of the 6 congruent circles, but a larger force G is needed to push the walls inward, lifting the circles. What is G/F? By @MarshallWBuck

A square containing a square with two extended sides. What is the blue fraction? mirangu.com/spiegel-im-spieg…

A quadrilateral with two diagonals and an inscribed circle. Prove that the three points are collinear. mirangu.com/wedged-in/

An ellipse with its focal points, major and minor axis. What is x, the distance from the centre to the right focal point? mirangu.com/egg-of-columbus/

Two quarter circles and a circle with a tangent line segment. What is pink : green? mirangu.com/the-roman-katapu… Inspired by @ChrisWildhagen

What is the green angle α between the cross ways? mirangu.com/kitty-corner-cro… By @MarshallWBuck

Two triangles are placed as shown. What is the angle α? mirangu.com/angle-chase/