Example

function skewY(
    $strokeColor, $fillColor, $backgroundColor, $fillModifiedColor,
    $startX, $startY, $endX, $endY, $skew
) {
    $draw = new \ImagickDraw();

    $draw->setStrokeColor($strokeColor);
    $draw->setStrokeWidth(2);
    $draw->setFillColor($fillColor);
    $draw->rectangle($startX, $startY, $endX, $endY);
    $draw->setFillColor($fillModifiedColor);
    $draw->skewY($skew);
    $draw->rectangle($startX, $startY, $endX, $endY);

    $image = new \Imagick();
    $image->newImage(500, 500, $backgroundColor);
    $image->setImageFormat("png");
    $image->drawImage($draw);

    header("Content-Type: image/png");
    echo $image->getImageBlob();
}