one person chooses, in his|her mind only a number N between 0 and 31
other start at node 16 and ask "is N smaller than 16?" ... if the answer is "yes", You will take the upper/left road leading to number 8 ... if the answer is "no", You will take the lower/right road leading to number 24
now You ask, "is N smaller than 8?" (or 24)...again, if the answer is "yes", You take the upper/left road (leading You to 4, resp. 20), in other case You take the lower/right road (leading You to 12, resp. 28)
You repeat two more times until You reach the leaves of the tree....if N is odd, the leaf node where You finished is the number N
(if number N is even, than it is one of those numbers which You traversed on Your path, e.g. 16,24,20 or 22 if You ended up at leaf 23)
then another person invents the number and others guess.
P.S. this binary tree will help You : https://kastalia.medienhaus.udk-berlin.de/7815
in March / April
choose a tree which has cca 20-30 cm diameter at 1m height
at 1m height, drill a cca 2cm-5cm hole with 0.5 cm diameter
insert a drinking straw or a glass tube
collect max 2-3 liters per tree
enclose the drill hole with earth/soil and ash (otherwise the tree could "bleed to death")
for a chosen tree, do not apply more often than once in 2 years
Birch provides four good things: she illuminates (used for torches); she strangles cries (birch tar used for creeking wheels); she heals the sick and she purifies (birch canes in sauna).