I2C is a "bus", which is a technical way of saying that you just connect
   all of the SDA pins together in a daisy chain, and likewise all of the SCL
   pins.  That's a big part of what makes I2C so popular: you can connect a
   large number of chips to a microcontroller like the Pico, while tying up
   only two of its GPIO pins, no matter how many chips you attach.  There
   are some technical limits to how many chips you can attach, but we're
   not likely to run up against them for a virtual pin cab set