Batch roundabout sys32

oof.bat

@echo off
:: Patterns for setting and expanding variables, based on a depth of 5

:: V(n) is a set representing the variable depth
:: V(0) = 0
:: V(1) = 1
:: V(2) = !1  -> V(2-1) * 3 - 2 = 1 * 3 - 2 = 1
:: V(3) = !5  -> V(3-1) * 3 + 2 = 1 * 3 + 2 = 5
:: V(4) = !13 -> V(4-1) * 3 - 2 = 5 * 3 - 2 = 13
:: V(n) = V(n-1) * 3 - 2; n is even; n > 1
:: V(n) = V(n-1) * 3 + 2; n is odd; n > 1

:: E(n) is a set representing variable expansion depth
:: E(0) = !(1)
:: E(1) = 3  -> E(1-1) * 2 + 1 = 1 * 2 + 1  = 3
:: E(2) = 7  -> E(2-1) * 2 + 1 = 3 * 2 + 1  = 7
:: E(3) = 15 -> E(3-1) * 2 + 1 = 7 * 2 + 1  = 15
:: E(4) = 31 -> E(4-1) * 2 + 1 = 15 * 2 + 1 = 31
:: E(n) = E(n-1) * 2 + 1; n > 0

:: Level 3
echo Level 3:
setlocal EnableDelayedExpansion
set a0=win
set %a0%=sys
call set !%a0%!=dir
call call set x=!a0!%%%a0%%%%%%%%%%a0%%%%%%%
for /f %%n in ('call echo %%%x%%%') do (
	echo %%n
)
echo.
echo Level 4:

:: Level 4
setlocal EnableDelayedExpansion
set a0=wi
set %a0%=n
call set !%a0%!=sys
call call set !%%%%%a0%%%%%!=dir
call call call set x=!a0!%%%a0%%%%%%%%%%a0%%%%%%%%%%%%%%%%%%%%%%a0%%%%%%%%%%%%%%%
for /f %%n in ('call echo %%%x%%%') do (
	echo %%n
)

echo.
echo Level 5:
:: Level 5
setlocal EnableDelayedExpansion
set a0=w
set %a0%=i
call set !%a0%!=n
call call set !%%%%%a0%%%%%!=sys
call call call set !%%%%%%%%%%%%%a0%%%%%%%%%%%%%!=dir

call call call call set x=!a0!%%%a0%%%%%%%%%%a0%%%%%%%%%%%%%%%%%%%%%%a0%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%a0%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
for /f %%n in ('call echo %%%x%%%') do (
	echo %%n
)

exit /B

:: Result %%n is the value of winsysdir in every instance