Cutle, from Pfiffel.com, gives you a shape and a single instruction: halve it precisely. You draw one straight line through the figure, and the aim is two pieces of identical area, which is harder than it sounds when the outline bulges on one side and narrows on the other. A round is one stroke. The gap between what looked even and what really was even is the reason to try again the next day.
Halfway comes first because it asks for the same straight cut and adds thirds and quarters. After it come a paper-folding puzzle, games that halve countries or 3D objects, then a slicing puzzle, and finally estimation and logic games for angles, areas and outlines that lean on the same eye for geometry.
The most direct match: one straight cut through a shape, except the target can be thirds or quarters as well as exact halves, which turns Cutle's single rule into a small set of different challenges.
Also plays with straight lines across a flat shape, but each line is a crease: you keep folding a paper sheet until its silhouette equals the one shown, and fewer folds mean a better result.
Takes the single straight line to a map: the day's country must be halved first by land area, next by where its people live, and finally on a bonus layer that is only shown after you commit.
Carries the halving idea into 3D: you angle a blade through five solid objects a day, trying to leave two parts that weigh the same, and a three-life endless mode waits when the set is done.
Keeps the slicing but asks what was sliced: an unseen 3D object passes through a blade, and from the flat cross-section shifting as the cut moves along, you work out what the object is.
Draws on the same sense of area: you judge how many identical circles could pack into the day's shape with none overlapping, one sample circle shows the size, and warmer or colder feedback guides five attempts.
Another quick geometry read by eye: an angle appears on screen and you estimate its size in degrees, adjusting from the feedback over four attempts, a close cousin of Cutle's judge-it-and-commit feel.
Shows a wedge cut from a circle and asks for its angle in degrees, telling you after each of four guesses if you went over or under, so the eye you train on Cutle's slices carries straight over.
Trains a quick eye for outlines: several candidate shapes appear and you pick the one that matches the reference, five shapes in a row, with no cutting but plenty of careful comparing.
Swaps area for accuracy of outline: you look at five shapes, sketch each again from memory, and are scored on how near your drawing comes, playing alone, with friends or in a live match.
Makes dividing up space a logic puzzle: rectangles must carve the grid so every piece contains a single number matching its cell count, on boards of 5x5, 7x7 or 9x9, and hints come with explanations.
Applies halving to numbers instead of area: each even pile breaks into two equal shares placed on adjacent cells, and the goal is a board where every target is met precisely, with undo available at easy, medium and hard sizes.
To cut the day's shape into two pieces of exactly equal area with one straight line. You get a single slice, so the challenge is judging where the middle of an irregular outline really lies before committing. Halfway, Halve and Halfsies all build on the same straight-cut idea with extra targets or new kinds of shapes.
Halfway uses the same one-cut rule but can ask for thirds or quarters as well as halves, which forces you to picture smaller portions of the area. For a geographic take, Halve splits a country by area and then by population, and Halfsies asks for equal weight in 3D objects.
