Prime Sieve Cotton Dress Shirt: Composite Numbers — Oxblood & Ivory
Prime Sieve Cotton Dress Shirt: Composite Numbers — Oxblood & Ivory
Giving it as a gift? Print its story card to tuck in with it.
Write the numbers in rows, and the primes fall into place.
More than two thousand years ago, Eratosthenes of Cyrene found the primes by crossing numbers out using a simple process: Remove every multiple of 2, then of 3, then of 5, and so on. Whatever survives can be divided only by itself and one. In this print every number is a dot: the pale ones crossed out, and the colored ones are prime.
If you write the numbers in rows, the width of the row decides the picture.
Composite Numbers. Rows 750 numbers wide. 750 is 2 × 3 × 5 × 5 × 5, so every multiple of 2, 3 and 5 falls into the same columns row after row. The primes can only live in the columns left over, and they gather into fine vertical stripes.
Who it’s for
Prime numbers guard almost everything sent over the internet: the encryption behind online banking and secure websites rests on how hard it is to split a large number into its primes. Made for cryptographers, security engineers, software developers, data scientists and anyone who has ever wondered why numbers are so strange.
A formal shirt with a conversation in it: for conference talks, thesis defenses, interviews, weddings and dinners. A thoughtful gift for the scientist, engineer or programmer with great taste.
Love this design? Make it yours.
Your colours, your occasion: a keynote, a wedding party, matching shirts for your team. We'll create it with you, made just for you.
Custom colours from US$150 · new designs from US$500
Start a custom order →The Cotton Dress Shirt
- Lightweight 100% cotton (110 g).
- Long sleeves with buttoned cuffs, collar and a single chest pocket.
- Printed edge to edge, across collar, cuffs and pocket.
- European sizing: please check the size guide below before ordering.
- Wash by hand or on a gentle cycle below 45 °C. Do not soak or bleach.
- Not quite the right fit? Tell us within 30 days and we’ll make it right.
Size guide
Measurements around the body, in cm (inches). Allow 1–3 cm either way.
| Size | Length | Chest | Shoulder | Sleeve |
|---|---|---|---|---|
| S | 74 (29.1) | 108 (42.5) | 52 (20.5) | 61 (24.0) |
| M | 76 (29.9) | 114 (44.9) | 53.5 (21.1) | 62 (24.4) |
| L | 78 (30.7) | 120 (47.2) | 55 (21.7) | 63 (24.8) |
| XL | 80 (31.5) | 126 (49.6) | 56.5 (22.2) | 64 (25.2) |
| 2XL | 82 (32.3) | 132 (52.0) | 58 (22.8) | 65 (25.6) |
| 3XL | 83 (32.7) | 140 (55.1) | 60 (23.6) | 66 (26.0) |
| 4XL | 84 (33.1) | 148 (58.3) | 62 (24.4) | 67 (26.4) |
| 5XL | 85 (33.5) | 156 (61.4) | 64 (25.2) | 68 (26.8) |
| 6XL | 86 (33.9) | 164 (64.6) | 68 (26.8) | 69 (27.2) |
Every Zenzicube design is grown from a real piece of mathematics. Find more in the Mathematical Menagerie.