# # toy example of a self-describing algebraic expression represented by a # tree of type %sfOZXT # # {qo[qQZwYQ[YR{LlbiXq_sZhRiAoJAeOvq?lBjR?HmT=Z@ygPKmCN^gNe`z=ZIgGwNt=gO@]cyPTXj^pntTTlSaPnWgmP` oDu{fUoJ`\QNf<=KmoF_xZ\wFctx`oPqL{Dp@wPgKOL_qlk{Pd?VnwqA\FAt DQM]oJFZFOuQHbHbSh{ofUnoF[^DS_moF\_\S_ctwFf<=cv>]Z Ve{Dp@t^{t