Keys.xml

<sequence values="BADGRIFYUP" origin="Center">
  <prl in="ABB*" out="*DDA"/>
  <one in="A" out="G" steps="1"/>
  <one steps="1">
    <rule in="A" out="R"/>
    <field for="R" from="G" on="RDA"/>
  </one>
  <one in="RDDA" out="*IYU" steps="1"/>
  <one temperature="2.0">
    <rule in="UDDA" out="FIYU"/>
    <rule in="UDDG" out="FIYG"/>
    <field for="U" to="G" on="GDAU"/>
  </one>
  <markov>
    <one in="UDDA" out="FIYU"/>
    <one in="IBB*/FDDA" out="P***/*IYU"/>
  </markov>
  <prl>
    <rule in="Y" out="F"/>
    <rule in="I" out="F"/>
    <rule in="D" out="B"/>
  </prl>
</sequence>

<!--
Generates a random puzzle with keys and locks.

Adapted graph grammar from the dissertation "Engineering Emergence. Applied Theory for Game Design" by Joris Dormans.
-->