Verification: the quadrilateral formed by the parallel lines which cross the vertex of the diamond and make diagonals to the outside of the diamond is a rectangle

Verification: the quadrilateral formed by the parallel lines which cross the vertex of the diamond and make diagonals to the outside of the diamond is a rectangle

From the meaning of the title
There are four parallel lines drawn outward, which can be divided into two groups and are parallel to each other,
It is known that two groups of parallelograms with opposite sides are parallelograms
The quadrilateral is a parallelogram
And because
The diamond diagonals are perpendicular to each other, so
The adjacent sides of the parallelogram are perpendicular to each other,
therefore
The quadrilateral formed by the parallel lines which cross the vertex of the diamond and make diagonals to the outside of the diamond is a rectangle

Through the four vertices of the rectangle, make parallel lines of diagonals respectively, and the enclosed quadrilateral is?

Firstly, the quadrilateral drawn is a parallelogram because two pairs of sides are parallel to each other;
Secondly, connect the diagonals of the parallelogram, and you will find that they are perpendicular to each other;
To sum up, it is a diamond