os.run( {}, "rom/programs/clear" )
print ( "Running SOS Beacon..." )

-- Put a sticky piston with something bright on top
local sSide = "top"
local nCount = 3
local nPeriod = 1

-- Redstone from the left will halt execution
while redstone.getInput( "left" ) ~= true do
  -- S:
  os.run( {}, "rom/programs/redpulse",
                  "top", nCount, nPeriod )

  -- O: not a pulse as such
  for n=1,nCount do
        redstone.setOutput( sSide, true )
        sleep( nPeriod*2 )
        redstone.setOutput( sSide, false )
        sleep( nPeriod )
  end

  -- S:
  os.run( {}, "rom/programs/redpulse",
                  "top", nCount, nPeriod )
end

print ( "Redstone execution halt signal detected." )