A device for a toilet bowl comprising: - at least two, preferably at least three, toilet rim blocks, which each consist of at least one shell and one core, wherein the shell comprises a first composition and the core comprises a second composition, wherein the first and the second composition preferably differ by at least one of the following features: different active ingredients, different concentration of the same active ingredient, different viscosity; wherein the shell surrounds the core in part, wherein the core projects, on at least one side of the toilet rim block, in the form of a pole, up to the surface and is exposed in the process, - means for holding the toilet rim block on the toilet bowl, wherein the toilet rim blocks are arranged so as to be irregular with respect to one another by at least one pole (4, 5), wherein the toilet rim blocks are spherical, wherein the toilet rim blocks are produced by a production method, wherein a co-extruded strand portion is placed in a press, wherein the final shape of the press is a sphere, the volume of which is identical to that of the strand portion, wherein cavities of the press are brought together and the final shape is thus achieved, wherein the strand portion is deformed to form a sphere. - at least two, preferably at least three, toilet rim blocks, which each consist of at least one shell and one core, wherein the shell comprises a first composition and the core comprises a second composition, wherein the first and the second composition preferably differ by at least one of the following features: different active ingredients, different concentration of the same active ingredient, different viscosity; wherein the shell surrounds the core in part, wherein the core projects, on at least one side of the toilet rim block, in the form of a pole, up to the surface and is exposed in the process, wherein the shell comprises a first composition and the core comprises a second composition, wherein the first and the second composition preferably differ by at least one of the following features: different active ingredients, different concentration of the same active ingredient, different viscosity; wherein the shell surrounds the core in part, wherein the core projects, on at least one side of the toilet rim block, in the form of a pole, up to the surface and is exposed in the process, - means for holding the toilet rim block on the toilet bowl, wherein the toilet rim blocks are arranged so as to be irregular with respect to one another by at least one pole (4, 5), wherein the toilet rim blocks are spherical, wherein the toilet rim blocks are produced by a production method, wherein a co-extruded strand portion is placed in a press, wherein the final shape of the press is a sphere, the volume of which is identical to that of the strand portion, wherein cavities of the press are brought together and the final shape is thus achieved, wherein the strand portion is deformed to form a sphere. wherein the toilet rim blocks are arranged so as to be irregular with respect to one another by at least one pole (4, 5), wherein the toilet rim blocks are spherical, wherein the toilet rim blocks are produced by a production method, wherein a co-extruded strand portion is placed in a press, wherein the final shape of the press is a sphere, the volume of which is identical to that of the strand portion, wherein cavities of the press are brought together and the final shape is thus achieved, wherein the strand portion is deformed to form a sphere.