A pure HTML/SVG/JS implementation of the famous Berlin Set Theory Clock (Mengenlehreuhr), located at the Europa-Center in Berlin since 1975. Designed by Dieter Binninger, it is the world’s first public clock to display time using set theory principles.

How to Read the Clock

The clock consists of 5 rows that encode hours, minutes, and seconds:

Row Elements Color Value
Top circle 1 lamp Yellow Blinks every even second
Row 1 4 blocks Red Each = 5 hours (max 20h)
Row 2 4 blocks Red Each = 1 hour (max 4h)
Row 3 11 blocks Yellow / Red Each = 5 minutes — every 3rd block (quarter hours) is red
Row 4 4 blocks Yellow Each = 1 minute (max 4 min)

Hours = (lit lamps in Row 1 × 5) + (lit lamps in Row 2) Minutes = (lit lamps in Row 3 × 5) + (lit lamps in Row 4) Seconds = top circle ON → even second, OFF → odd second

Features

  • Pure SVG rendering — crisp at any resolution
  • CSS glow effects for an authentic neon look
  • Digital time display below the clock
  • Updates every second
  • Progressive Web App (PWA) — installable on mobile and desktop
  • Works offline via Service Worker caching
  • Zero dependencies — just a single self-contained HTML file

Try it out: Live Demo

Source code on GitHub.