RAINBOW FLAG contains multitudes. Multitudes of Unicode characters, that is, because ‘🏳️🌈’ is conjured into existence only if four other characters are placed in order, one after another.1 Nor is it the only such flag, or even the only such emoji; a surprisingly large number of emoji comprise two or more individual characters. By my count, the current version of Unicode admits of 2,760 such emoji2,3 out of 3,953 in total.4
These two-kids-in-a-trenchcoat emoji take many forms. There are those, such as HOT SPRINGS (♨️), which add a so-called variation selector to an older, monochrome symbol to signal that it should be rendered as an emoji. Certain abbreviations made of special “regional indicator” letters magically turn into country flags, such as Liechtenstein’s (🇱🇮), which comprises the regional indicators ‘🇱’ and ‘🇮’. Yet others marry a generic emoji (☝) to one of a selection of special skin-tone emoji (🏾️) to gain a more realistic appearance (☝🏾).2 And others are even more ambitious: this innocuous emoji (👩🏽❤️💋👩🏻) is made up of no fewer than four others (‘👩🏽’, ‘❤️’, ‘💋’ and ‘👩🏻’), not to mention that some of those four emoji are also made up of more than one individual character. Oh, and it has a sprinkling of special, invisible “joiner” characters, too.3
That there are so many emoji like this is at least partly because Unicode’s emoji subcommittee got bored of having to formally standardise every last emoji that crossed its desk.5 From 2015 onwards, the consortium started to lean on composite emoji as a way to quickly add new symbols to the emoji repertoire. RAINBOW FLAG arrived in 2016 as just such a character, comprising WAVING WHITE FLAG (🏳︎), RAINBOW (🌈), a variation selector to turn ‘🏳︎’ into ‘🏳️’ and a joiner character to glue the whole thing together.6 Hooray!
And then iPhones started crashing.7
A computer science student named Preston Petrie had worked out that a particular series of characters, similar but not identical to those inside RAINBOW FLAG, would cause the iPhone’s text processing engine to fail, and fail hard.8 The offending string looked like this: “🏳️0🌈”, with a ‘0’ interposed between the constituent parts of the RAINBOW FLAG. Remove that ‘0’ and everything was fine; leave it in, and any iPhone which received the string would freeze and then crash.9
A slew of media coverage ensued, but Apple moved quickly to get ahead of the story. Just a few days later, the company pushed out an update to the iPhone’s operating system to fix the bug10 and the furore soon died down. Yet the fact remains that for a time, a broken emoji was enough to break an iPhone. It’s easy to forget how bewilderingly complex our computers, smartphones and software are — and, correspondingly, how brittle they can be, too. And every now and again, a rainbow flag comes along to remind us.
- 1.
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Davis, Mark. “L2/16-183:/Rainbow/Flag/Emoji”. Unicode Consortium, July 19, 2016.
- 2.
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Unicode.org. “Emoji-sequences.Txt”. Accessed November 13, 2025.
- 3.
- Unknown entry ↢
- 4.
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Emojipedia. “Emoji Statistics”. Accessed November 13, 2025.
- 5.
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Davis, Mark, Peter Edberg, and . “L2/15-252:/Unicode/Customized/Emoji/(UCE)/Proposal”. Unicode Consortium, n.d.
- 6.
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Emojipedia. “🌈 Rainbow Emoji”. Accessed November 14, 2025.
- 7.
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Gibbs, Samuel. “Prank crashes iPhones with rainbow emoji messages”. The Guardian, sec. Technology.
- 8.
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Petrie, Preston. “Reckless Rainbow Bug”. preston159.com.
- 9.
- 10.