/*Source*/
import Lsystem;
size(8cm,0);
Lsystem Fass=Lsystem("-L",
new string[][]{{"L","LFLF+RFR+FLFL-FRF-LFL-FR+F+RF-LFL-FRFRFR+"},
{"R","-LFLFLF+RFR+FL-F-LF+RFR+FLF+RFRF-LFL-FRFR"}},
La=90);
Fass.iterate(3);
draw(Fass.paths(), linewidth(1bp));
shipout(bbox(Fill(lightgrey)));