Let the lines ℓB and ℓC meet at LA; define the points LB and LC similarly. Note that the sidelines of the triangle LALBLC are perpendicular to the corresponding sidelines of ABC. Points OA,OB,OC are located on the corresponding sidelines of LALBLC; moreover, OA,OB, OC all lie on the perpendicular bisector of OP.

Claim 1. The points LB,P,OA, and OC are concyclic.
Proof. Since O is symmetric to P in OAOC, we have
(O A P, O C P )= (O C O, O A O )= (C P, A P)= (C B, A B)= (O A L B , O C L B ) .
Denote the circle through LB,P,OA and OC by ωB. Define the circles ωA and ωC similarly.
Claim 2. The circumcircle of the triangle LALBLC passes through P.
Proof. From cyclic quadruples of points in the circles ωB and ωC, we have
(L C L A , L C P ) = (L C O B , L C P )= (O A O B , O A P ) = (O A O C , O A P )= (L B O C , L B P )= (L B L A , L B P ) .
Claim 3. The points P,LC, and C are collinear.
Proof. We have (P L C , L C L A )= (P L C , L C O B )= (P O A , O A O B ). Further, since OA is the centre of the circle AOP, (P O A , O A O B )= (P A, A O). As O is the circumcentre of the triangle P C A, (P A, A O)= / 2- (C A, C P)= (C P, L C L A ). We obtain (P L C , L C L A )= (C P, L C L A ), which shows that P∈CLC.
Similarly, the points P,LA,A are collinear, and the points P,LB,B are also collinear. Finally, the computation above also shows that
(O P, P L A )= (P A, A O)= (P L C , L C L A ),
which means that OP is tangent to the circle PLALBLC.