The Raspberry Pi Minecraft API has a little known function for reporting which blocks "Steve" has hit/mined as he moves around the world. Naturally enough, it is called pollBlockHits and returns a list of hit objects that includes the coordinate for each hit. The list is refreshed each time the function is called so if nothing has been hit for a while, the list may be empty. We can use it in a script to do some planting by using the sword as a sort of magic wand.

while True:
  hits = world.events.pollBlockHits()

  for hit in hits:
    world.setBlock(hit.pos.x, hit.pos.y, hit.pos.z, block.FLOWER_CYAN)

  sleep(0.5)