The method of inverse geometry: We place a spherical cage in the desert and enter it. We then perform an inverse operation with respect to the cage. The lion is then inside the cage and we are outside.
The set theoretic method: We observe that the desert is a separable space. It therefore contains an enumerable dense set of points from which can be extracted a sequence having the lion as the limit. We then approach the lion stealthily along this sequence bearing with us suitable equipment.
The Dirac method: We observe that wild lions are ipso facto not observable in the Sahara desert. Consequently if there are any lions in the Sahara, they are tame. The capture of a tame lion is left as an exercise for the reader.
The thermodynamic method: We construct a semi-permeable membrane which is permeable to everything except lions and sweep it across the Sahara.
