HEAD
----

[graphviz]
----
digraph {
  node [style=bold, shape=circle, color="#385d8a", fontname=arial, fontsize=18]
	edge [style=bold, color="#385d8a", arrowhead=none]

  F -> E -> B -> A
  D -> C
  C -> B [weight=0]

	edge [arrowhead=normal]
	node [shape=box, style=filled, fillcolor=lightgrey, color=black]
	HEAD [style=dashed, color=grey, fontcolor=grey]
  "origin/master" [fillcolor=lightskyblue]

  HEAD -> feature1 [style=dashed, color=grey]
  feature1 -> D
  "origin/master" -> E
  bugfix15 -> F

  { rank=same; F; D; bugfix15; feature1 }
  { rank=same; "origin/master"; E; C }

  D -> F [style=invis]
  C -> E [style=invis]

  HEAD1 [color=red, fillcolor=red, fontcolor=white, label=HEAD]
  HEAD1 -> bugfix15 [color=red]
}
----

[role="incremental"]
* `checkout` moves `HEAD`
* `checkout` also updates the working tree