Collection
What happens inside the machine: objects, methods, operators, slicing and sorting in Python, visible step by step.
Apps
The numbers in a[i:j] are cuts between the cells: two handles for start and stop glide along a ruler with positive numbers above and negative ones below, the expression stays in sync, and the result appears exactly as in Python 3.13. a[1:3] gives two cells, a[2:100] is cut off, a[7] is an IndexError, a[5:2] is empty, a[5:1:-1] runs backwards. Plus index and del modes, strings with a TypeError on change, six tasks and predictions.
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Python expressions step by step: the expression tree hangs right below the expression — what goes first sits at the bottom — and the 14-level precedence ladder shows why. Values fly up, the intermediate state substitutes sub-expressions, and/or short circuits stay visibly unevaluated. 17 examples from the lecture notes (a += a == 2, -2 ** 2, 3 > 2 > 1 …), your own expressions, a guess beforehand and a “misconception” reading (strictly left to right, times before divided, powers from the left …) to compare.
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Bubble, Insertion and Selection Sort in a race: three lanes sort the same list at the same tick, one tick being one comparison. Bars glide past each other when they swap, counters show comparisons and swaps. With 5, 2, 9, 1, 7, 3 Insertion is done after 11 comparisons, Bubble and Selection after 15; sorted, Insertion needs 5. Single view with the pseudocode and Python of the slides, predictions, and doubling up to n = 102400 next to the times from the slide.
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Class as a blueprint, objects as cards: create runs, set attributes by hand and compute the total distance. A typo silently creates a new attribute; Python only complains when it is read (with “Did you mean”). The __init__ switch shows how a constructor guarantees complete objects. The generated program behaves the same in real Python; four tasks.
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Slow motion for Lauf(8.5, 53.5) and l.tempo(): the rewrite strip turns l.tempo() into Lauf.tempo(l); the object before the dot slides into the parentheses and becomes self. The constructor first creates an empty object and fills it through self; whatever is not attached to self disappears with the frame. Methods live only on the class card and two objects share them. Plus self passed in the call (TypeError) and the forgotten self. (AttributeError).
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A tower of object, Wettkampf, Lauf and object: for w.tempo(), print(w) or l.platz a search beam climbs station by station, and the first match wins. tempo lives only in Lauf, all attributes sit in the one object, and super() continues the search one level up. Switching methods off shows which version of __str__ takes over, all the way up to object.
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A training log with an interface (eintragen, gesamtstrecke) and an X-ray view of its inside: three versions store the runs in completely different ways. The program that only uses the methods works in all three versions; the program that reaches into the inside breaks with the first rebuild. The underscore does not protect either; it is a request.
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Which method does a * b call? A flow diagram shows the two stations a.__mul__(b) and b.__rmul__(a) with the exits result, NotImplemented and error. With numbers, strings, lists, fractions in four stages (isinstance, __rmul__, __eq__) and runs with and without __lt__: why 3 * Bruch(1, 2) first fails at the int and then ends up in __rmul__.
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The MIU system from Gödel, Escher, Bach to touch: the word is made of tiles, four rule cards show where MxI → MxIU, Mx → Mxx, xIIIy → xUy and xUUy → xy fit, and a tap applies the rule. Above it the derivation tree grows level by level as on the slide, optionally as a breadth-first search without repetitions (1, 2, 3, 5, 14, 44, 213 new words). The I counter with the remainder on division by 3 and the five proof cases show why MU never appears.
Computer scienceTry itCollections
Planning and steering projects: the iron triangle, stakeholders, network diagrams, earned value, schedule risk, team size, Kanban and waterfall against Scrum.
8 appsOpen collection
From sequences to loans: arithmetic and geometric growth, savings plans, annuities, compounding within the year and perpetuities.
11 appsOpen collection
Reading the traces: burial mounds in section, radiocarbon dating, settlements in the landscape and the tomb of Tutankhamun.
5 appsOpen collection
Why robot arms are heavy, how six axes guide a hand and how control holds the load.
4 appsOpen collection
Tables, keys, joins, groups and subqueries you can touch: how a database really reads.
7 appsOpen collection
Generative AI in strong images: what it can do, how it writes, why it convinces, how to use it well and where to take care.
7 appsOpen collection
Engine, brakes, high voltage, CAN bus and chassis: technology and diagnostics of the modern vehicle.
9 appsOpen collection
Heat in the city centre: heat islands, shade, trees and unsealing, using the old town of Reutlingen as an example.
5 appsOpen collection
Reading the small print, spotting subscription traps, placing risk figures and making texts understandable.
4 appsOpen collection
From equation to curve: initial values, linear equations, substitution and the worlds in which they apply.
7 appsOpen collection
Mean, median, mode, box plot and levels of measurement: descriptive statistics to try out.
9 appsOpen collection
From coordinates to the inverse: vectors, dot and cross products, linear equations and matrices in pictures.
12 appsOpen collection
Production principles, waste, one-piece flow, value streams, bills of materials and routing: how a factory is organised.
6 appsOpen collection
What the CRA requires of manufacturers: checking whether it applies, meeting reporting deadlines, keeping software bills of materials.
5 appsOpen collection
Reducing, common denominators, multiplying, dividing and mixed numbers: fractions step by step.
7 appsOpen collection
Proofs of special beauty to touch: Zagier's windmills, the museum guards and Buffon's needle.
3 appsOpen collection
How oscillations break down: coefficients, symmetry, phasor chains, the Gibbs phenomenon and the plucked string.
7 appsOpen collection
From the Patent Motor Car to the Z3: famous machines and experiments cut open in 3D.
11 appsOpen collection
Keyboard, intervals, scales, chords, the circle of fifths and groove: music theory you hear and play.
9 appsOpen collection
How sound is made and shaped: synthesizers and samplers, envelopes and overtones, waveforms and timbre, voice and orchestra, room acoustics and sound scenography — all audible in your browser.
16 appsOpen collection
Staging space, sight, light, sound and paths: visitor flows, showcase lighting, room acoustics, sound islands, projection mapping and the pavilions of world expos to try out.
15 appsOpen collection
Mathematical questions open for decades, for which an AI model proposed solutions in 2026, as interactive apps: understand the problem, experience the result.
32 appsOpen collection
From neurons and gradients to transformers, RLHF and agents: machine learning you can touch.
44 appsOpen collection
DNA, replication, transcription, translation and cell division as explorable 3D models.
24 appsOpen collection
Perspective, ornament, structure and space: how art and architecture work with mathematics.
21 appsOpen collection
Hyperloop, autonomous vehicles, warehouses and conveyors: logistics as interactive simulation.
17 appsOpen collection
Heart, eye, voice, skeleton and nerves: the human body in 3D, layer by layer.
10 appsOpen collection
Monty Hall, Simpson, Berkson and base rates: where intuition fails us with numbers.
14 appsOpen collection
Planets, stars, black holes and space probes: the cosmos to explore.
10 appsOpen collection
Light switches for nerve cells, a telescope made of ice, mirror-image chemistry and interest rates: the 2026 Nobel Prizes to try out.
8 appsOpen collection
Planted participants, smoke in the room, one dollar for a lie and experimenters who are themselves the subjects: famous social psychology experiments to try yourself.
5 appsOpen collection
Relations, classes, orders, bijections, different infinities and topology: mathematics as the science of structure, hands-on.
11 appsOpen collection
Riemann, P vs NP, Poincaré and other great questions of mathematics, made tangible.
16 appsOpen collection
Counting, arithmetic and shapes: maths for beginners, playful and clear.
6 appsOpen collectionWant to use these apps in your courses? Let’s find out what works for you.
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