Using multiple screenshots inside exists()

One more question...
The script I'm trying to build is something like a little farmer bot, so it click on some wheat, then clicks on "reap" button and repeats that action. What would be the easiest way to take current mouse position (or position of the last click on "reap" button) and to find closest available wheat target next to this current?

--- first question

which = None
while True:
    if exists(button1, 0):
        which = "button1"
        break
    if exists(button2, 0):
        which = "button2"
        break
    wait(1)
if which == "button1":
    print "Found Button 1"
elif which == "button2":
    print "Found Button 2"
else:
    print "should never happen ;-)"

--- second question

lastClick = getLastMatch() # center of last clicked/found image
current = Region(lastClick.x, lastClick.y, 1, 1) # where we want to look around
nearest = current.nearby(100).find(wheat)

nearest = current.nearby(100).find(wheat)

Can you explain that syntax to me please?

@ Albert
see docs: http://sikuli.org/docx/region.html#extending-a-region

BTW: Just found, the above snippet uses upper left corner of last match.
if you want to use center:

LastClick = getLastMatch().getCenter() # center of last clicked/found image
current = Region(lastClick.x, lastClick.y, 1, 1) # where we want to look around
nearest = current.nearby(100).find(wheat)

Hi,
First post ever. But related to the first one. I have used following syntax when there is multiple images to use and there is no need for infinite waiting:

if exists(image1, 0) or exists(image2, 0):
    click(getLastMatch())
else:
    # Do something if images not found