remove the box frame pieces, all pieces are of the extended lineage

Signed-off-by: Brian S. Stephan <bss@incorporeal.org>

src/frames/pieces/side-trapezoid-extended-to-front-trapezoid.scad

@@ -0,0 +1,38 @@
+/*
+ * SPDX-FileCopyrightText: © 2024 Brian S. Stephan <bss@incorporeal.org>
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+include <parameters.scad>
+include <components.scad>
+use <frames/complete/left-frame.scad>
+use <side.scad>
+use <front-or-back-trapezoid.scad>
+
+module side_and_bottom_frame_piece_wall() {
+	// get a slice of the pieces, to use it in extruding
+	// this doesn't use the side_frame_piece because of the 45 degree angle geometry
+	// not creating a clean thing to cut, so we just take the whole wall and use that
+	projection(cut=true) rotate([0, 90, 0]) translate([frame_x/2-frame_wall-(frame_bevel_height/2), 0, 0])
+		left_frame();
+	projection(cut=true) translate([0, -frame_y/2+frame_wall, 0]) rotate([90, 90, 0]) bottom_piece_extension();
+}
+
+module side_and_bottom_frame_piece_extension() {
+	// combine the original with a shrunken piece to "pull" the wall out
+	hull() {
+		linear_extrude(height=frame_extension_y) scale([0.5, 0.90, 1]) side_and_bottom_frame_piece_wall();
+		linear_extrude(height=frame_bevel_height) side_and_bottom_frame_piece_wall();
+	}
+}
+
+module side_trapezoid_extended_to_front_frame_piece() {
+	difference() {
+		side_frame_piece();
+		// chop off the old edge which is getting replaced with the extension
+		translate([-frame_x/2+frame_bevel_height/2, 0, 0]) cube([frame_bevel_height, frame_y, frame_z], center=true);
+	}
+	translate([-frame_x/2+frame_bevel_height*2, 0, 0]) rotate([0, -90, 0]) side_and_bottom_frame_piece_extension();
+}
+
+side_trapezoid_extended_to_front_frame_piece();