Chess960: two move ideas no. 8

Here is another great idea courtesy of game I found on onlinechesslessons.net this time between two super GM's Aronian and Nakamura. The amazing idea is to actually block the bishops in the corner with your own pawns in a cat and mouse attempt to delay exchanging off the bishops in the corner until just the right time:

SP451 white to play: try to see black's ideas

Enjoy 960

Hint: black has managed to discourage white from moving either c4, d4 or e4.
If 3. d4!? white blocks the a1 bishop on the long diagonal allowing black to play 3 ... f5!
If white instead plays 3.e4?! the light bishop on h1 is trapped for a very long time.