Design a $1$m x $1$m window capable of maintaining the temperature of

a $1\mathrm{.}2$ x $1\mathrm{.}2$ x $0\mathrm{.}8$ furnace at a near constant temperature $($within a few

degrees of initial temperature$)$ over the timespan $20$ minutes, assuming

the outside temperature is $0$C and the required inside temperature is

$100$C$.$ Discuss variables such as window thickness, number of layers and

the gas between window layers

Note: Assume the $1$m x $1$m window will be centralised on the $1\mathrm{.}2$m x

$1\mathrm{.}2$m furnace face, and that the furnace will be at $100$C initially with no heat source