[\~] 1 xx *

##</code><code>##

    pugs> .say for [\~] 1 xx 10
    1
    11
    111
    1111
    11111
    111111
    1111111
    11111111
    111111111
    1111111111

##</code><code>##

    1...{$_~1}

##</code><code>##

    1,11,111,1111 ... {$^previous ~ 1}

##</code><code>##

1,*~1...*
1, 11, 111, 1111, {$^previous ~ 1} ... *