linkage![
.define_param("x/y view", 0.58333)
.define_param("z", 0.39)
.define_param("zoom", 0.5)
.pen_up()
.up_param("z", -3.0, 0.0)
.forward_param("zoom", -10.0, 20.0)
.pitch_param("z", 0.0, -90.0)
.yaw_param("x/y view", 180.0, -180.0)
.mark("scene origin")
.pen_down()
]