JavaScriptが記号だけで書ける言語であることはよく知られています。 たとえば、以下のようなプログラムを実行すればHello, World!とコンソールに表示されますね。 [][[[][[[[]==[]]+[]][+[]][+[]]+[[+[]==[]]+[+[]]+[][+[]]+[]][+[]][++[+[]][+[]]+[+[]]]+[[+[]==[]]+[][+[]]][+[]][++[+[]][+[]]+[+[]]]+[[][+[]]+[]][+[]][++[++[+[]][+[]]][+[]]]][[]]=[[][[[[]==[]]+[]][+[]][+[]]+[[+[]==[]]+[+[]]+[][+[]]+[]][+[]][++[+[]][+[]]+[+[]]]+[[+[]==[]]+[][+[]]][+[]][++[+[]][+[]]+[+[]]]+[[][+[]]
![本格JavaScript記号プログラミング(1) 6種類の記号だけでJavaScriptを書こう - Qiita](https://cdn-ak-scissors.b.st-hatena.com/image/square/b3287146238e64568eec878db4686abd544b8131/height=288;version=1;width=512/https%3A%2F%2Fqiita-user-contents.imgix.net%2Fhttps%253A%252F%252Fcdn.qiita.com%252Fassets%252Fpublic%252Farticle-ogp-background-412672c5f0600ab9a64263b751f1bc81.png%3Fixlib%3Drb-4.0.0%26w%3D1200%26mark64%3DaHR0cHM6Ly9xaWl0YS11c2VyLWNvbnRlbnRzLmltZ2l4Lm5ldC9-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%26mark-x%3D142%26mark-y%3D57%26blend64%3DaHR0cHM6Ly9xaWl0YS11c2VyLWNvbnRlbnRzLmltZ2l4Lm5ldC9-dGV4dD9peGxpYj1yYi00LjAuMCZoPTc2Jnc9NzcwJnR4dD0lNDBUYXRhbW8mdHh0LWNvbG9yPSUyMzIxMjEyMSZ0eHQtZm9udD1IaXJhZ2lubyUyMFNhbnMlMjBXNiZ0eHQtc2l6ZT0zNiZ0eHQtYWxpZ249bGVmdCUyQ3RvcCZzPWRlYWIzYzEwYjlkNzU4Mzc0ZWExMzgyZTFkMTI5YTI1%26blend-x%3D142%26blend-y%3D436%26blend-mode%3Dnormal%26txt64%3DaW4g5qCq5byP5Lya56S-44OH44Kj44O844O744Ko44OM44O744Ko44O8%26txt-width%3D770%26txt-clip%3Dend%252Cellipsis%26txt-color%3D%2523212121%26txt-font%3DHiragino%2520Sans%2520W6%26txt-size%3D36%26txt-x%3D156%26txt-y%3D536%26s%3D460854a0f7886276506d55d80cd2cf57)