For ($year=1; $year -le 15; $year++ ) {
    mkdir "vst/year$(([string]$year).PadLeft(2, '0'))"

    For ($day=1; $day -le 8; $day++) {
        Invoke-WebRequest https://vst.ninja/DB$year/synced_data/day$day.csv -o "vst/year$(([string]$year).PadLeft(2, '0'))/day$day.csv"
    }
}