Obsidian farm code for computercraft

print("How much obsidian do you want to create")
print()
print("1. 7 blocks")
print("2. 14 blocks")
print("3. 21 blocks")
print("4. 28 blocks")
print("5. 35 blocks")
print()
print("Number: ")
a=tonumber(read())
local i=0
repeat
--Deployers color first
rs.setBundledOutput("bottom", colors.combine(rs.getBundledOutput("bottom"),colors.black))
sleep(1.0)
rs.setBundledOutput("bottom", colors.subtract(rs.getBundledOutput("bottom"),colors.black))
sleep(1.0)
--Dispensers color second
rs.setBundledOutput("bottom", colors.combine(rs.getBundledOutput("bottom"),colors.white))
sleep(1.5)
rs.setBundledOutput("bottom", colors.subtract(rs.getBundledOutput("bottom"),colors.white))
sleep(3.0)
rs.setBundledOutput("bottom", colors.combine(rs.getBundledOutput("bottom"),colors.white))
sleep(1.5)
rs.setBundledOutput("bottom", colors.subtract(rs.getBundledOutput("bottom"),colors.white))
sleep(1.0)
--Optional section for pistons/something else--
--rs.setBundledOutput("bottom", colors.combine(rs.getBundledOutput("bottom"),colors.orange))
--sleep(1.0)
--rs.setBundledOutput("bottom", colors.subtract(rs.getBundledOutput("bottom"),colors.orange))
--sleep(1.0)
--Block breaker color last
rs.setBundledOutput("bottom", colors.combine(rs.getBundledOutput("bottom"),colors.green))
sleep(1.0)
rs.setBundledOutput("bottom", colors.subtract(rs.getBundledOutput("bottom"),colors.green))
sleep(1.0)
i=i+1
until i==a
print("Enjoy your Obsidian")