" 'An intentional killing is premeditated and deliberate if it occurred as the result of preexisting thought and reflection rather than unconsidered or rash impulse.'" (People v. Jurado (2006) 38 Cal.4th 72, 118.) " ' "The true test is not the duration of time as much as it is the extent of the reflection. . . ." ' " (People v. Bolin (1998) 18 Cal.4th 297, 332.) The time needed to reflect on the pending killing may be short. "First degree willful, deliberate, and premeditated murder involves a cold, calculated judgment, including one arrived at quickly." (People v. Carasi (2008) 44 Cal.4th 1263, 1306.) On the other hand, "the legislative classification of murder into two degrees would be meaningless if 'deliberation' and 'premeditation' were construed as requiring no more reflection than may be involved in the mere formation of a specific intent to kill." (People v. Anderson (1968) 70 Cal.2d 15, 26.) In People v. Anderson, supra, 70 Cal.2d 15, the court set forth a test for sufficiency of the evidence of premeditation and deliberation. Under that test, three main kinds of circumstances give evidentiary support to a murder conviction based on premeditation and deliberation, namely planning activity, motive, and manner of killing. "To sustain a verdict of premeditated and deliberate murder, Anderson required: (1) extremely strong evidence of planning; (2) evidence of motive in conjunction with evidence of planning or of a calculated manner of killing, or; (3) evidence of all three indicia of premeditation and deliberation." (People v. Memro (1995) 11 Cal.4th 786, 863; see Anderson, supra, at p. 27.) As early as People v. Perez (1992) 2 Cal.4th 1117, the California Supreme Court was cautioning that "the Anderson guidelines are descriptive, not normative" (id. at p. 1125); they are not "exhaustive" (ibid.). Since Perez, the court has stated that the Anderson factors " 'need not be present in any particular combination to find substantial evidence of premeditation and deliberation.'" (People v. Jurado, supra, 38 Cal.4th at pp. 118-119.) The California Supreme Court has shown signs of moving well away from the strict Anderson formula in some cases, while in others it continues to adhere to it. (Compare People v. Hovarter (2008) 44 Cal.4th 983, 1019, with People v. Carasi, supra, 44 Cal.4th at p. 1306, and People v. San Nicolas (2004) 34 Cal.4th 614, 658.)