---
name: "Math::PlanePath::DekkingCentres"
section: "3pm"
platform: "linux"
package: "libmath-planepath-perl"
version: "129-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/Math::PlanePath::DekkingCentres"
---

# Math::PlanePath::DekkingCentres(3pm)

## NAME

Math::PlanePath::DekkingCentres -- 5x5 self-similar

## SYNOPSIS

```
 use Math::PlanePath::DekkingCentres;
 my $path = Math::PlanePath::DekkingCentres->new;
 my ($x, $y) = $path->n_to_xy (123);
```

## DESCRIPTION

This is a variation on a 5x5 self-similar curve from

F. M. Dekking, "Recurrent Sets", Advances in Mathematics, volume 44, 1982, pages 79-104, section 4.9 "Gosper-Type Curves"

and which is a horizontal mirror image of the E-curve of McKenna 1978.

The form visits the "centres" of the 5x5 self-similar unit squares of the pattern.  The result is some diagonal steps, but replications wholly within 5x5 areas.

```
                              ...
        |                     /
      9 |  115-116 122-123-124  89--88  86--85--84
        |    |   |    \          |    \  |       |
      8 |  114 117-118 121-120  90  92  87  82--83
        |    |        \   /      |/   \      |
      7 |  113-112 106 119 102  91  94--93  81  77
        |     /   /  |    /  |    /       /   /  |
      6 |  111 107 105 103 101  95--96  80  78  76
        |    |    \   \  |   |        \   \  |   |
      5 |  110-109-108 104 100--99--98--97  79  75
        |                                         \
      4 |   10--11  13--14--15  35--36  38--39--40  74  70  66--65--64
        |    |    \  |       |   |    \  |       |   |   |\   \      |
      3 |    9   7  12  17--16  34  32  37  42--41  73  71  69  67  63
        |    |/   \      |       |/   \      |       |/      |/   /
      2 |    8   5-- 6  18  22  33  30--31  43  47  72  55  68  62--61
        |      /      /   /  |    /       /   /  |    /   \          |
      1 |    4-- 3  19  21  23  29--28  44  46  48  54--53  56--57  60
        |         \   \  |   |        \   \  |   |        \      |   |
    Y=0 |    0-- 1-- 2  20  24--25--26--27  45  49--50--51--52  58--59
        +---------------------------------------------------------------
           X=0   1   2   3   4   5   6   7   8   9  10  11  12  13  14
```

The base pattern is the N=0 to N=24 section.  It repeats with rotations or reversals which make the ends join.  For example N=75 to N=99 is the base pattern in reverse.  Or N=50 to N=74 is reverse and also rotate by -90.

## FUNCTIONS

See "FUNCTIONS" in Math::PlanePath the behaviour common to all path classes.

- "$path = Math::PlanePath::DekkingCentres-\>new ()"

  Create and return a new path object.

- "($x,$y) = $path-\>n\_to\_xy ($n)"

  Return the X,Y coordinates of point number `$n` on the path.  Points begin at 0 and if `"$n < 0"` then the return is an empty list.

### Level Methods

- "($n\_lo, $n\_hi) = $path-\>level\_to\_n\_range($level)"

  Return `"(0, 25**$level - 1)"`.

## SEE ALSO

Math::PlanePath, Math::PlanePath::DekkingCurve, Math::PlanePath::CincoCurve, Math::PlanePath::PeanoCurve

## HOME PAGE

\<http://user42.tuxfamily.org/math-planepath/index.html\>

## LICENSE

Copyright 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020 Kevin Ryde

This file is part of Math-PlanePath.

Math-PlanePath is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version.

Math-PlanePath is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with Math-PlanePath.  If not, see \<http://www.gnu.org/licenses/\>.