The Shear mapping effect transforms your images in a plane. Starting from a shear center, all other points are shifted in parallel. For example, rectangular photos and videos are displayed as a parallelogram with correspondingly distorted content. You can find the effect in the Toolbox under the Objects tab in the Live effects section.

You can add Flexi-Collages or other effects to the effect besides single images, videos, text objects.

Drag the Shear mapping effect from the Toolbox to the Timeline.

To insert an image into the effect, drag it from the Toolbox's File Browser into the Shear mapping object.

If an image already exists in the Timeline, you can drag the effect from the Toolbox directly onto the image.

In the Name field, you can enter a name for the effect. This improves the overview in the Timeline.

Set the shear angle and the shear center.

To animate the orientation of the Shear mapping, i.e. to change it via the display duration, select the Curve icon, which is located on the right in each case.

Step 1: Create layout

Insert the Dynamic Rectangle shape into the first track of a Chapter object. This serves as the background.

In the track below, drag the Layout effect. Fill the Layout effect with four photos. Portrait images are particularly suitable for this.
In the Timeline, arrange the photos in the Layout effect one below the other.

Set the Layout effect in its Properties to Layout: Horizontal (even). Select as Margin: 0% and as Space: 10%.

Now collapse the Layout effect in the Timeline.

Step 2: Add Shear mapping to layout

Drag the Shear mapping effect from the Toolbox onto the collapsed Layout effect in the Timeline. When a colored Apply Template marker appears on the Layout effect, release the mouse.

The Layout effect is now in the Shear mapping effect.
 
In the Properties of the Shear mapping effect, set the Shearing angle for the X axis: 15%. The Layout now appears skewed.
 
Optionally, drag the selection frame of the Shear mapping effect in the Layout designer slightly larger so that the white corners of the slanted layout (top left and bottom right) are no longer visible.