Cursor over parts to see sizes
all centimetres unless stated otherwise

skittle

stiff-card-rectangle any-size

shown-here-about 3-x-6

support

2-pieces-softwood
about-1-x-1-x-5

ramp

stiff-card-rectangle
15-to-20cm-long
3-to-4cm-wide

2-pieces

marbles

at-least-one marble-or-wooden bead

marble-best because-it-is heavier

Skittle support

softwood
no-bigger-than
1-x-1-x-2