plotIsOnAnIsland.lua

function plotIsOnAnIsland(pPlot)

  local canGoOnLand
  canGoOnLand = function (pStartingPlot, iDirection, iDistance, iDirectionConstraint)

    if iDirectionConstraint == nil then
      iDirectionConstraint = iDirection
    end

    local directionMeetsConstraint = function(dir)
      return (math.abs(iDirectionConstraint-dir) < 2 or math.abs(iDirectionConstraint-dir) > 4)
    end

    local pCurrentPlot = pStartingPlot

    pCurrentPlot = Map.GetAdjacentPlot(pCurrentPlot:GetX(), pCurrentPlot:GetY(), iDirection)

    if pCurrentPlot and pCurrentPlot:IsWater() then
      return false
    end

    if iDistance == 1 then
      return true
    else
      local directionFan = { (iDirection-1) % 6, iDirection, (iDirection+1) % 6}

      for _, iNextDirection in ipairs(directionFan) do
        if directionMeetsConstraint(iNextDirection) then
          if canGoOnLand(pCurrentPlot, iNextDirection, iDistance-1, iDirectionConstraint) then
            return true
          end
        end
      end

    end

    return false
  end

  for iDirection = 0,5 do
    local pCurrentPlot = pPlot
    if canGoOnLand(pCurrentPlot, iDirection, 3) then
      return false
    end
  end

  return true
end