-- | Given to numbers, creates a list of half-hours intervals between them
-- modifies 12-hour representation to 24
makeSlots :: Double -> Double -> [Double]
makeSlots start end
    | end < start = halfHourSlots start (12 + end)
    | start < 8.5 = halfHourSlots (start + 12) (end + 12)
    | otherwise   = halfHourSlots start end
makeSlots :: Double -> Double -> [Double]
makeSlots start end
    | end < start = halfHourSlots start (12 + end)
    | start < 8.5 = halfHourSlots (start + 12) (end + 12)
    | otherwise   = halfHourSlots start end
makeSlots start end
    | end < start = halfHourSlots start (12 + end)
    | start < 8.5 = halfHourSlots (start + 12) (end + 12)
    | otherwise   = halfHourSlots start end