Day 2 : Restoration Challenge

A question is hidden in plain sight on this classic work of art - parts of the question are unclear, obscured by debris. Clear the particlesof debrisby selecting pairs that are separated by one space - they will merge into one particle. When there is only one particle left, the question will be revealed.

Again, the actual puzzle varies - there appear to be many different configurations. But it's quite simple - it's like the game of solitaire (no, not the Windows card game thing) where you jump counters. Once you get the hang of it, it's quite simple. An example is here (starting) and here (finish).

Once you have completed the puzzle, you are given a question:

Name the symbol on Manuel Aringarosa, pictured at left

Answer: Greek Cross.