Rectangles with size and position controlled by parent
<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" HorizontalAlignment="Stretch" VerticalAlignment="Stretch"> <Grid> <Grid.ColumnDefinitions> <ColumnDefinition /> <ColumnDefinition /> </Grid.ColumnDefinitions> <Grid.RowDefinitions> <RowDefinition /> <RowDefinition /> </Grid.RowDefinitions> <Rectangle Grid.Column="0" Grid.Row="0" Fill="Red" /> <Rectangle Grid.Column="1" Grid.Row="0" Fill="Black" /> <Rectangle Grid.Column="0" Grid.Row="1" Fill="Yellow" /> <Rectangle Grid.Column="1" Grid.Row="1" Fill="White" /> </Grid> </Page>