Mathematical and Physical Journal
for High Schools
Issued by the MATFUND Foundation
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# Problem I. 357. (October 2014)

I. 357. Moiré patterns are unwanted patterns turning up on posters, digital photographs, or on images consisting of straight lines or regular structures. They are caused by interference on the repeating patterns, and they often make the work of a graphic designer harder. Moirés can also form on finely woven fabrics or on the surface of long straight hair, but they also appear on fences and grids consisting of solid vertical lines and repeated geometric units.

Create and save an animation in an SVG vector graphics file showing the formation of a simple moiré pattern. Most browsers (with the exception of Internet Explorer) are capable of displaying SVG files properly. A description of the SVG file structure and the animations can be found at http://svg.elte.hu/. We recommend using the (freely downloadable) Inkscape vector graphics editor.

You can create the figures (such as striped squares in the simplest case, point clouds or other striped shapes) appearing in your animation with the vector graphics editor. The animation should be done by editing the text of the image file.

The shapes should be overlaid on top of each other by rotating or translating them at appropriate speeds so that the moiré becomes visible. You are free to choose the playing time, the number of repetitions or other parameters.

The image file (i357.svg) together with a short analysis of the code creating the animation (i357.txt, i357.pdf, ...) should be submitted.

(10 pont)

Deadline expired on November 10, 2014.

### Statistics:

 15 students sent a solution. 10 points: Bálint Martin, Dér Leonóra, Dombai Tamás, Kovács Balázs Marcell. 9 points: Fényes Balázs, Hamrik Szabin, Kazal Soma, Lencsés Ádám, Nagy Ábel, Olexó Gergely, Rittgasszer Ákos, Tóth Márk Andor. 8 points: 2 students. Unfair, not evaluated: 1 solutions.

Problems in Information Technology of KöMaL, October 2014