A 2 year old child is seen on a routine visit in the pediatric clinic. Abdominal examination demonstrates a palpable, non-tender mass on the left side of the abdomen. The mother had no idea the mass was present and the pediatrician did not note the presence of the mass at the child's 18-month's visit for immunisation. Physical examination is otherwise unremarkable. If a CT guided biopsy of the mass were performed, which of the following histological patterns would be most suggestive of the likely diagnosis?