@echo off
setlocal enabledelayedexpansion

set "myREGEX=%1"
set "REGEX="
set /a count=0

:loop_start
set /a count=!count! + 1

if !count! leq 10 (
if !count! equ 1 (
set "REGEX=!myREGEX!"
) else (
set "REGEX=!REGEX! !myREGEX!"
)
echo !REGEX!
goto :loop_start
)

endlocal
pause