Y by
Let
be an acute triangle with the orthocenter
. On the segments
and
, we choose three points
and
respectively such that
. Denote by
,
and
.
a) Prove that the sides of the hexagon
are tangent to the one circle.
b) Let
be a incenter of the hexagon
. Prove that the lines
and
are concurrent.










a) Prove that the sides of the hexagon

b) Let



