Boxes and structure
===================

The box is the basic building block. A box with a label is a single line:

.. sheeptext::
   :alt: A box labelled hello

   box "hello"

Give shapes names (identifiers) so you can refer to them later. A name goes
before a colon:

.. sheeptext::
   :alt: Two named boxes, client and server

   Client: box "Client"
   Server: box "Server"

Lines starting with ``//`` are comments and are ignored when rendering:

.. sheeptext::
   :alt: A single box, with a comment line above it

   // the entry point of the system
   box "start here"

A box sizes itself to its label, but you can set an explicit ``width`` or
``height``. Unpositioned boxes flow left to right, and ``gap`` sets the space
before a box in that flow:

.. sheeptext::
   :alt: A wide box, then a taller box set well apart, then a third box tucked close

   A: box "wide" width 150
   B: box "tall" height 80 gap 30
   C: box "snug" gap 4

Next: connect boxes with :doc:`arrows`.