What a beautiful molecule. Tert.-butyl radical is the quintessential example of a tertiary radical. This radical derives its thermodynamic stability from the combined electron donating ability of three methyl groups. In addition, the three groups provide a certain degree of steric shielding of the radical center and give rise to a kinetic stabilization as well. The central C-atom is clearly pyramidalized to some degree. As we have seen in the ethyl and sec,-propyl radicals, all three methyl groups are lined up so that one C-H bond aligned with the orbital that carries the unpaired electron. Note that the aligned C-H bonds are pointing in the direction opposite to the direction in which the "lone radical" is pointing!