Revision control
++ <?xml version="1.0" encoding="UTF-8"?>
++ <!--
++ orthogonal preemption - inner or states interrupt one-another
++ in our semantics, source state is at the same level of hierarchy, so document order will resolve conflict. a1 will win.
++ -->
++ <scxml
++ datamodel="ecmascript"
++ xmlns="http://www.w3.org/2005/07/scxml"
++ version="1.0"
++ initial="b">
++
++ <parallel id="b">
++ <parallel id="c">
++ <state id="e">
++ <transition event="t" target="a1"/>
++ </state>
++
++ <state id="f">
++ <transition event="t" target="a2"/>
++ </state>
++
++ <transition event="t" target="a3"/>
++ </parallel>
++
++ <state id="d">
++ <transition event="t" target="a4"/>
++ </state>
++
++ </parallel>
++
++ <state id="a1"/>
++
++ <state id="a2"/>
++
++ <state id="a3"/>
++
++ <state id="a4"/>
++
++ </scxml>