In Chrysoberyl parlance, a gewgaw is the digital version of a bagatelle (music) or a doodle (visual art). It almost always involves visuals (usually animated), sometimes audio, and occasionally interaction.

A gewgaw need not be implemented in HTML5, but many of Cat's Eye Technologies' gewgaws are, and you can can experience them here, online, right in your web browser.

Note that the distinctions between a Gewgaw and an Automaton or even a Game are not always clear, and entries here may be categorized somewhat arbitrarily, and you might want to check those articles too.

A Minimalist Critique of Tetris


A minimalist critique of Tetris.

A Non-Random Walk


This is an animated version of the "non-random walk" on p. 72 of Mathematical Circus by Martin Gardner.

Art Restoration Simulator


A simulator that lets you experience the thrills and spills of the fascinating world of art restoration.

Bézier Knots

Knots made of Bézier curves.

Black Hole Poem


An interactive concrete poem about black holes.

Canvas Feedback


An application of an analogue-video-like feedback effect to an HTML5 canvas element, with in-browser controls by which the feedback properties can be adjusted. For some background and an explanation of how it works, see its README document.

Circus Xamulus


A circle-based time-lapse space-filler.



An attempt to make some generative art with as much coour contrast as possible, or at least, a lot of colour contrast.

Eine kleine Glitchfraktal


A simple fractal (each rectangle contains four smaller rectangles) with colour variance and configurable glitching.

Fibonacci Spiral


A spiral made up of semicircles with proportions in the Fibonacci sequence.



A simple interactive entertainment, intended to be experienced on a touchscreen device.

This is most certainly a gewgaw. It should provide you about 20 seconds of entertainment, give or take.

Heronsis hermnonicii


An animated "plate" depicting a proto-cohort of Heronsis hermnonicii.

Warning: the following may contain tedious and/or glib background and/or analysis.

Casting a negative space of knowledge. Calling itself a "plate" frames it as a work of learning, like some kind of 19th-century anthropology text. Yet it only raises questions — what are these entities? what kind of world do they inhabit? what are they protecting? who is Clarkson? — without providing answers, leaving it up to the observer to either imagine their own answers, or decide that answers to these questions are not necessary.

Plus it's fun to click on the red balls.

Hirsute Miasma


Your web browser is burdened by the sins of its ancestors and their shower drains.



"Hypongtrochoid" is a portmanteau of hypotrochoid (as popularized by Spirograph) and Pong (as popularized by, well, Pong.)

Kolakoski Kurve


This is a geometric interpretation of the Kolakoski sequence (also known as the "see and say" sequence) using turtle graphics: 1 means turn while 2 means go forward (roughly speaking.)


Most recursive fractals are created top-down: start with a big thing, add some smaller things to it, add some even smaller things to those things, etc.

I was curious about what it would be like if a fractal was generated bottom-up: start with many small things, connect them to larger things, then connect those to even larger things, etc.

This is the result of implementing that method.


A "livetextmangler" — an online tool which transforms text. As you select different filters to apply to the input, the output is updated in real-time. Can also be used on the command-line.

Markov Font

Uses a 2D Markov chain to generate new glyphs from a character set.



Animated op art: an interactive bleeding of colours.

Noise to Signal No. 1


A generated animation involving randomness and not-so-much randomness.



An animated impressionistic depiction of the prairies.

I composed this while still in Winnipeg and still learning about the capabilities of <canvas> — something about the wind and the wheat... The background is a public-domain drawing of a grain elevator taken from Wikimedia.



Animated op-art exhibiting a moiré effect.

A real eye-tickler. This was one of the first bits of <canvas> code I ever wrote; I essentially wrote it by accident — it wasn't quite what I meant, but I liked it, and kept it. For me, in Firefox, it starts getting interesting around 100 iterations, and starts stopping being interesting around 1550. In Chromium, you can still see some activity at about 2000 iterations, but it's very faint thereafter.



An animated mathematical function, depicted in four different ways.



Randomly-assembled street map or circuit or something similar to these.

Semicircle Jam

A path made of semicircles.

Tentacles, Undamped


A simulation of undulating tentacles. It starts off alright, but soon starts doing things real tentacles never do, because real tentacles have damping.

Text Uniquifier

An online tool/amusement where you paste in some text and it displays the text with repeated words removed.

The Frame


An interactive exploration of the concept of The Frame in art, based on words and 'do by Frank Zappa.

This piece was conceived and begun in late summer or early autumn of 2012, in Winnipeg, and finished up and released from Cornwall in spring of 2013.

The Judgment of Paris


A slight reworking of a well-known Greek myth.

Two Fifty Six


A graphical depiction of the first two hundred and fifty-six natural numbers, in base four, using coloured squares with potentially varying assignments of colours to digits.

Uncle Ankur


An experimental animation employing gradients and randomly-constructed transformation matrices.

Woman on Film


An interactive, navigable, animated thing based on several tracings of a still from a film.