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Furthermore, one to three crests can be defined. The first crest is mandatory and only contains the relativeLevel attribute. The second and third crests also must contain the width attribute. User has the choice between entering one of the following:
- singleCrest: to define only crest1
- doubleCrest: to define crest1 and crest2
- tripleCrest: to define crest1, crest2 and crest3
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