To create a text string in VisualAPL which contains the backslash [\] character, consideration has to be given to the fact than in VisualAPL the backslash is a escape character (like in c#).
Several options are available including escape the backslash [i.e. double the backslash] or precede the string data containing the backslash with the @ symbol. For example:
( '\\gris' '\\morado' '\\naranja' '\\verde')
Or
( @'\gris' @'\morado' @'\naranja' @'\verde')
For an APL'er not familiar with Microsoft Visual Studio 2005 and C#, this syntax looks strange, but is is necessary to maintain full interoperability of VisualAPL with C# and other .Net languages.