Someone

startshape tree

rule tree  .5 {
	shape {}
	treeleft {}
}

rule tree  .5 {
	shape {}
	treeright {}
}

rule treeleft 1 {
	shape {}
	treeleft {s .95 y 2 r -3}
}

rule treeright 1 {
	shape {}
	treeright {b .04 s .95 y 2 r 3}
}

rule treeright  .125 {
	branch{s .8}
}

rule treeleft  .125 {
	branch{s .8}
}

rule branch {
	CIRCLE {s 1.3}
	tree {r 45 x -1.414 y 1.414}
	tree {r -45 x 1.414 y 1.414}
}

rule shape {
	SQUARE{}
}