Floyd's triangle

Here's two ways of doing it.

constant @floyd1 = (1..*).rotor(1..*);
constant @floyd2 = gather for 1..* -> $s { take [++$ xx $s] }

sub format-rows(@f) {
    my @table;
    my @formats = @f[@f-1].map: {"%{.chars}s"}
    for @f -> @row {
        @table.push: (@row Z @formats).map: -> ($i, $f) { $i.fmt($f) }
    }
    join "\n", @table;
}

say format-rows(@floyd1[^5]);
say '';
say format-rows(@floyd2[^14]);

Output:

 1 
 2  3 
 4  5  6 
 7  8  9 10 
11 12 13 14 15
 
 1 
 2  3 
 4  5  6 
 7  8  9 10 
11 12 13 14 15 
16 17 18 19 20 21 
22 23 24 25 26 27 28 
29 30 31 32 33 34 35 36 
37 38 39 40 41 42 43 44  45 
46 47 48 49 50 51 52 53  54  55 
56 57 58 59 60 61 62 63  64  65  66 
67 68 69 70 71 72 73 74  75  76  77  78 
79 80 81 82 83 84 85 86  87  88  89  90  91 
92 93 94 95 96 97 98 99 100 101 102 103 104 105