**cone, point up:**is where the vertex points up.**cone, point down:**is where the vertex points down.**sphere:**a body the surface of which is at all points equidistant from the centre. (The New Shorter Oxford English Dictionary. 1993. vol 2) spheres are commonly used as International Association of Lighthouse Authorities - IALA topmarks (safe water).**2 spheres:**two black spheres are commonly used as an International Association of Lighthouse Authorities - IALA topmark (isolated danger).**cylinder:**a solid geometrical figure generated by straight lines fixed in direction and describing with one of point a closed curve, especially a circle (in which case the figure is circular cylinder, it's ends being parallel circles). (The New Shorter Oxford English Dictionary. 1993. vol 2). cylinders are commonly used as International Association of Lighthouse Authorities - IALA topmarks (lateral).**board:**usually of rectangular shape, made from timber or metal and used to provide a contrast with the natural background of a daymark. The actual daymark is often painted on to this board.**x-shape:**having a shape or a cross-section like the capital letter X. (The New Shorter Oxford English Dictionary. 1993. vol 2) an x-shape as an International Association of Lighthouse Authorities - IALA topmark should be 3 dimensional in shape. It is made of at least three crossed bars.**upright cross:**a cross with one vertical member and one horizontal member, i.e. similar in shape to the character '+'.**cube:**a solid contained by six equal squares; a regular hexahedron (The New Shorter Oxford English Dictionary. 1993. vol 2) cube, point up: a cube standing on one of its vertexes.**cube, point up:**a cube standing standing on one of its vertexes.**2 cones, point to point:**2 cones, one above the other, with their vertices together in the centre.**2 cones, base to base:**2 cones, one above the other, with their bases together in the centre and their vertices pointing up and down.**rhombus:**a plane figure having four equal sides and equal opposite angles (two acute and two obtuse); an oblique equilateral parallelogram. (The New Shorter Oxford English Dictionary. 1993. vol 2)**besom:**a bundle of rods or twigs. (The New Shorter Oxford English Dictionary. 1993. vol 1) perch: a staff placed on top of a buoy, rock or shoal as a mark for navigation. (IHO Dictionary, S-32, 5th Edition, 3734)**perch:**a staff placed on top of a buoy , rock or shoal as a mark for navigation. (IHO Dictionary, S-32, 5th Edition, 3734)**flag:**a flag mounted on a short pole.**sphere over rhombus:**A sphere located above a rhombus.**square:**a plane figure with four right angles and four equal straight sides (The New Shorter Oxford English Dictionary. 1993. vol 2)**rectangle:**a plane figure with four right angles and four straight sides, opposite sides being parallel and equal in length (The New Shorter Oxford English Dictionary. 1993. vol 2) horizontal rectangle: where the two longer opposite sides are standing horizontally. vertical rectangle: where the two longer opposite sides are standing vertically.**horizontal rectangle:**where the two longer opposite sides are standing horizontally.**vertital rectangle:**where the two longer opposite sides are standing vertically.**trapezium:**a quadrilateral having one pair of opposite sides parallel. (The New Shorter Oxford English Dictionary. 1993. vol 2) trapezium, up: which stands on its longer parallel side. trapezium, down: which stands on its shorter parallel side.**trapezium up:**which stands on its longer parallel side.**trapezium down:**which stands on its shorter parallel side.**triangle:**a figure having three angles and three sides. (New Shorter Oxford English Dictionary. 1993. vol 2)**circle:**a perfectly round plane figure whose circumference is everywhere equidistant from its centre. (The New Shorter Oxford English Dictionary. 1993. vol 1)**two upright crosses:**two upright crosses, generally vertically disposed one above the other.**T-shape:**having a shape like the capital letter T.**triangle pointing up over a circle:**a triangle, vertex uppermost, located above a circle.**upright cross over a circle:**an upright cross located above a circle.**rhombus over a circle:**a rhombus located above a circle.**circle over a triangle pointing up a circle located over a triangle, vertex uppermost.**

**References**:

INT 1: IQ 9;

S-4: 463.1 (for International Association of Lighthouse Authorities - IALA systems only)