Let's call what we are doing here a 'first pass'.
Bosting usually consists of a number of 'passes': the block loses its squareness; ghostly shapes emerge, becoming ever clearer. In the beginning you can take biggish bites out of the wood, even using a coping saw.
'Bosting' - it's a carver's term for a bit more than just 'roughing out'. We are consciously looking for the main forms and how they join and flow together (in other words, how these forms'articulate').