How to: Create Multi-Column Report - Across the Page and Then Down

Telerik Report Soln
Out of the box Telerik Reporting offers multi-column reports with data flow - down the page and then across. How to set up this report layout is elaborated in the How to: Create a Multi-Column Report help article. However in some cases you may need a multi-column report layout with data flow across the page and then down.

Solution:
Due to the data driven nature of Telerik Reporting this can be easily achieved with ourTable/Crosstab/List item and indexed data as elaborated in the following steps:
Add a List item to your report definition;
Set the List.DataSource according to your datasource. For more info see:Connecting to Data help articles;
Open the Group Explorer in extended mode;
Set the (Detail) row group Grouping expression to:
=Fields.MyDataIndex/3
Where the number should equal the number of expected columns.
Set the (Static) column group Grouping expression to:
=Fields.MyDataIndex%3
Where the number should equal the number of expected columns.
Add the necessary items to the List item's Panel;
Preview the report.